Cell culture process

ABSTRACT

Polypeptides having target levels of C-terminal variants are described.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of U.S. provisionalapplication Ser. No. 61/505,681, filed on Jul. 8, 2011, the contents ofwhich are herein incorporated by reference in their entirety.

FIELD OF THE INVENTION

The invention relates generally to cell culture methods.

BACKGROUND

Therapeutic polypeptides are an important class of therapeuticbiotechnology products, and therapeutic antibodies (including murine,chimeric, humanized and human antibodies and fragments thereof) accountfor the majority of therapeutic biologic products.

SUMMARY

In one aspect, the invention features a method of producing a populationof recombinant polypeptides, comprising: providing a target value ofC-terminal variants of a recombinant polypeptide, providing a host cellcomprising a nucleic acid encoding the recombinant polypeptide,culturing the host cell under conditions (i) in which the cell expressesa population of C-terminal variants of the encoded recombinantpolypeptide and (ii) which increase the intracellular pH of the cell,and isolating the population, wherein the population comprises theprovided target value of C-terminal variants of the recombinantpolypeptide.

In some embodiments, the conditions which increase the intracellular pHof the cell comprise culturing the cells in a medium comprising one ormore of: (a) about 1 g/L to about 50 g/L lysine, arginine and/orhistidine; (b) about 0.1 g/L glucose to about 10 g/L glucose; (c) about2 mM to about 10 mM NH₄Cl; (d) about 10 μM to about 500 μM chloroquine;and (e) about 10 mM to about 30 mM glutamine.

In some embodiments, intracellular pH is increased by at least about10%, at least about 20%, at least about 30%, at least about 40%, atleast about 50%, at least about 60%, at least about 70%, at least about80%, at least about 90%, at least about 100%, or more, relative tocontrol culture conditions. In some embodiments, intracellular pH isincreased by a value of at least about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6,0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1,2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, or more, relative to controlculture conditions.

In some embodiments, the target value is a level of polypeptidescomprising a lysine or an arginine residue at a carboxyl terminus. Insome embodiments, the target value is a level of polypeptides comprisinga lysine or an arginine residue at a carboxyl terminus relative to a sumof a level of polypeptides comprising a lysine or an arginine residue ata carboxyl terminus and a level of polypeptides not comprising a lysineor an arginine residue at a carboxyl terminus. In some embodiments, thelevel of polypeptides comprising a lysine or an arginine residue at acarboxyl terminus relative to the sum of the level of polypeptidescomprising a lysine or an arginine residue at a carboxyl terminus andthe level of polypeptides not comprising a lysine or an arginine residueat a carboxyl terminus is about 0.1, about 0.2, about 0.3, about 0.4,about 0.5, about 0.6, about 0.7, about 0.8, about 0.9, or about 1.

In some embodiments, the recombinant polypeptide is a recombinantFc-containing polypeptide (e.g., antibody). In some embodiments, thetarget value is a level of heavy chains in the population comprising aC-terminal lysine or arginine. In some embodiments, the target value isa level of heavy chains having a C-terminal lysine or arginine in thepopulation of at least about 1%, at least about 2%, at least about 3%,at least about 4%, at least about 5%, at least about 6%, at least about7%, at least about 8%, at least about 9%, at least about 10%, at leastabout 11%, at least about 12%, at least about 13%, at least about 14%,at least about 15%, at least about 16%, at least about 17%, at leastabout 18%, at least about 19%, at least about 20%, at least about 25%,at least about 30%, at least about 35%, at least about 40%, at leastabout 45%, at least about 50%, or more. In some embodiments, the targetvalue is a level of K1 lysine variants and/or K2 lysine variants in thepopulation. In some embodiments, the target value is a level of K1lysine variants and/or K2 lysine variants in the population of at leastabout 1%, at least about 2%, at least about 3%, at least about 4%, atleast about 5%, at least about 6%, at least about 7%, at least about 8%,at least about 9%, at least about 10%, at least about 11%, at leastabout 12%, at least about 13%, at least about 14%, at least about 15%,at least about 16%, at least about 17%, at least about 18%, at leastabout 19%, at least about 20%, at least about 25%, at least about 30%,at least about 35%, at least about 40%, at least about 45%, at leastabout 50%, or more.

In some embodiments, the method further comprises measuring a level ofone or more C-terminal variants in the population. In some embodiments,the population is a population of Fc-containing polypeptides orantibodies, and the method further comprises measuring a level of one ormore of K0, K1, or K2 lysine variants in the population. In someembodiments, the method further comprises recording the level of one ormore of K0, K1, or K2 lysine variants in a print or computer-readablemedium, e.g., in a test report, Material Safety Data Sheet (MSDS) orCertificate of Testing or Certificate of Analysis (CofA).

In another aspect, the invention features a method of producing apopulation of Fc-containing polypeptides, comprising: providing a targetvalue of K0, K1, and/or K2 lysine variants of an Fc-containingpolypeptide; providing a host cell comprising a nucleic acid encodingthe Fc-containing polypeptide; culturing the host cell under conditions(i) in which the cell expresses a population of K0, K1, and/or K2 lysinevariants of the encoded Fc-containing polypeptide and (ii) whichincrease the intracellular pH of the cell; and isolating the population,wherein the population comprises the provided target value of K0, K1,and/or K2 lysine variants of the Fc-containing polypeptide.

In some embodiments, the conditions which increase the intracellular pHof the cell comprise culturing the cells in a medium comprising one ormore of: (a) about 2 g/L to about 50 g/L lysine, arginine and/orhistidine; (b) about 0.1 g/L glucose to about 10 g/L glucose; (c) about2 mM to about 10 mM NH₄Cl; (d) about 10 μM to about 500 μM chloroquine;and (e) about 10 mM to about 30 mM glutamine.

In some embodiments, the conditions which increase the intracellular pHof the cell comprise culturing the cells in a medium comprising one ormore of: (a) at least about 1 g/L lysine, arginine or histidine; (b)about 0.5 g/L glucose to about 2 g/L glucose; (c) about 2 mM to about 10mM NH₄Cl; (d) about 10 μM to about 500 μM chloroquine; and (e) about 10mM to about 30 mM glutamine.

In some embodiments, intracellular pH is increased by at least about10%, at least about 20%, at least about 30%, at least about 40%, atleast about 50%, at least about 60%, at least about 70%, at least about80%, at least about 90%, at least about 100%, or more, relative tocontrol culture conditions. In some embodiments, intracellular pH isincreased by a value of at least about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6,0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1,2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, or more, relative to controlculture conditions.

In some embodiments, the target value is a level of Fc-containingpolypeptides comprising a lysine or an arginine residue at a carboxylterminus. In some embodiments, the target value is a level ofFc-containing polypeptides comprising a lysine or an arginine residue ata carboxyl terminus relative to a sum of a level of Fc-containingpolypeptides comprising a lysine or an arginine residue at a carboxylterminus and a level of Fc-containing polypeptides not comprising alysine or an arginine residue at a carboxyl terminus. In someembodiments, the level of Fc-containing polypeptides comprising a lysineor an arginine residue at a carboxyl terminus relative to the sum of thelevel of Fc-containing polypeptides comprising a lysine or an arginineresidue at a carboxyl terminus and the level of Fc-containingpolypeptides not comprising a lysine or an arginine residue at acarboxyl terminus is about 0.1, about 0.2, about 0.3, about 0.4, about0.5, about 0.6, about 0.7, about 0.8, about 0.9, or about 1.

In some embodiments, the target value is a level of heavy chains in thepopulation comprising a C-terminal lysine or arginine. In someembodiments, the target value is a level of heavy chains having aC-terminal lysine or arginine in the population of at least about 1%, atleast about 2%, at least about 3%, at least about 4%, at least about 5%,at least about 6%, at least about 7%, at least about 8%, at least about9%, at least about 10%, at least about 11%, at least about 12%, at leastabout 13%, at least about 14%, at least about 15%, at least about 16%,at least about 17%, at least about 18%, at least about 19%, at leastabout 20%, at least about 25%, at least about 30%, at least about 35%,at least about 40%, at least about 45%, at least about 50%, or more. Insome embodiments, the target value is a level of K1 lysine variantsand/or K2 lysine variants in the population. In some embodiments, thetarget value is a level of K1 lysine variants and/or K2 lysine variantsin the population of at least about 1%, at least about 2%, at leastabout 3%, at least about 4%, at least about 5%, at least about 6%, atleast about 7%, at least about 8%, at least about 9%, at least about10%, at least about 11%, at least about 12%, at least about 13%, atleast about 14%, at least about 15%, at least about 16%, at least about17%, at least about 18%, at least about 19%, at least about 20%, atleast about 25%, at least about 30%, at least about 35%, at least about40%, at least about 45%, at least about 50%, or more.

In some embodiments, the method further comprises measuring a level ofone or more of K0, K1, or K2 lysine variants in the population. In someembodiments, the method further comprises recording the level of one ormore of K0, K1, or K2 lysine variants in a print or computer-readablemedium, e.g., in a test report, Material Safety Data Sheet (MSDS) orCertificate of Testing or Certificate of Analysis (CofA).

In another aspect, the invention features a method of producing apopulation of antibodies, comprising: providing a target value of K0,K1, and/or K2 lysine variants of an antibody; providing a host cellcomprising a nucleic acid encoding the antibody; culturing the host cellunder conditions (i) in which the cell expresses a population of K0, K1,and/or K2 lysine variants of the encoded antibody and (ii) whichincrease the intracellular pH of the cell; and isolating the population,wherein the population comprises the provided target value of K0, K1,and/or K2 lysine variants of the antibody.

In some embodiments, the conditions which increase the intracellular pHof the cell comprise culturing the cells in a medium comprising one ormore of: (a) about 2 g/L to about 50 g/L lysine, arginine and/orhistidine; (b) about 0.1 g/L glucose to about 10 g/L glucose; (c) about2 mM to about 10 mM NH₄Cl; (d) about 10 μM to about 500 μM chloroquine;and (e) about 10 mM to about 30 mM glutamine.

In some embodiments, intracellular pH is increased by at least about10%, at least about 20%, at least about 30%, at least about 40%, atleast about 50%, at least about 60%, at least about 70%, at least about80%, at least about 90%, at least about 100%, or more, relative tocontrol culture conditions. In some embodiments, intracellular pH isincreased by a value of at least about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6,0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1,2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, or more, relative to controlculture conditions.

In some embodiments, the target value is a level of antibodiescomprising a lysine or an arginine residue at a carboxyl terminus. Insome embodiments, the target value is a level of antibodies comprising alysine or an arginine residue at a carboxyl terminus relative to a sumof a level of antibodies comprising a lysine or an arginine residue at acarboxyl terminus and a level of antibodies not comprising a lysine oran arginine residue at a carboxyl terminus. In some embodiments, thelevel of antibodies comprising a lysine or an arginine residue at acarboxyl terminus relative to the sum of the level of antibodiescomprising a lysine or an arginine residue at a carboxyl terminus andthe level of antibodies not comprising a lysine or an arginine residueat a carboxyl terminus is about 0.1, about 0.2, about 0.3, about 0.4,about 0.5, about 0.6, about 0.7, about 0.8, about 0.9, or about 1.

In some embodiments, the target value is a level of heavy chains in thepopulation comprising a C-terminal lysine or arginine. In someembodiments, the target value is a level of heavy chains having aC-terminal lysine or arginine in the population of at least about 1%, atleast about 2%, at least about 3%, at least about 4%, at least about 5%,at least about 6%, at least about 7%, at least about 8%, at least about9%, at least about 10%, at least about 11%, at least about 12%, at leastabout 13%, at least about 14%, at least about 15%, at least about 16%,at least about 17%, at least about 18%, at least about 19%, at leastabout 20%, at least about 25%, at least about 30%, at least about 35%,at least about 40%, at least about 45%, at least about 50%, or more. Insome embodiments, the target value is a level of K1 lysine variantsand/or K2 lysine variants in the population. In some embodiments, thetarget value is a level of K1 lysine variants and/or K2 lysine variantsin the population of at least about 1%, at least about 2%, at leastabout 3%, at least about 4%, at least about 5%, at least about 6%, atleast about 7%, at least about 8%, at least about 9%, at least about10%, at least about 11%, at least about 12%, at least about 13%, atleast about 14%, at least about 15%, at least about 16%, at least about17%, at least about 18%, at least about 19%, at least about 20%, atleast about 25%, at least about 30%, at least about 35%, at least about40%, at least about 45%, at least about 50%, or more.

In some embodiments, the method further comprises measuring a level ofone or more of K0, K1, or K2 lysine variants in the population. In someembodiments, the method further comprises recording the level of one ormore of K0, K1, or K2 lysine variants in a print or computer-readablemedium, e.g., in a test report, Material Safety Data Sheet (MSDS) orCertificate of Testing or Certificate of Analysis (CofA).

In another aspect, the invention features a method of producing apopulation of recombinant antibodies, comprising: providing a targetvalue of C-terminal variants of a recombinant antibody, providing a hostcell comprising a nucleic acid encoding the recombinant antibody,culturing the host cell in a medium comprising about 2 g/L to about 50g/L lysine, arginine and/or histidine under conditions in which the cellexpresses a population of C-terminal variants of the encoded recombinantantibody; and isolating the population, wherein the population comprisesthe provided target value of C-terminal variants of the recombinantantibody.

In some embodiments, the medium comprises lysine, arginine, histidine,or a combination of lysine, arginine, and/or histidine, at aconcentration of at least about 1.5 g/L, at least about 2 g/L, at leastabout 2.5 g/L, at least about 3 g/L, at least about 3.5 g/L, at leastabout 4 g/L, at least about 4.5 g/L, at least about 5 g/L, at leastabout 5.5 g/L, at least about 6 g/L, at least about 6.5 g/L, at leastabout 7 g/L, at least about 7.5 g/L, at least about 8 g/L, at leastabout 8.5 g/L, at least about 9 g/L, at least about 9.5 g/L, at leastabout 10 g/L, at least about 10.5 g/L, at least about 11 g/L, at leastabout 11.5 g/L, at least about 12 g/L, at least about 12.5 g/L, at leastabout 13 g/L, at least about 13.5 g/L, at least about 14 g/L, at leastabout 14.5 g/L, at least about 15 g/L, at least about 15.5 g/L, at leastabout 16 g/L, at least about 16.5 g/L, at least about 17 g/L, at leastabout 17.5 g/L, at least about 18 g/L, at least about 18.5 g/L, at leastabout 19 g/L, at least about 19.5 g/L, at least about 20 g/L, at leastabout 25 g/L, at least about 30 g/L, at least about 35 g/L, at leastabout 40 g/L, at least about 45 g/L, at least about 50 g/L, or more.

In some embodiments, the target value is a level of antibodiescomprising a lysine or an arginine residue at a carboxyl terminus. Insome embodiments, the target value is a level of antibodies comprising alysine or an arginine residue at a carboxyl terminus relative to a sumof a level of antibodies comprising a lysine or an arginine residue at acarboxyl terminus and a level of antibodies not comprising a lysine oran arginine residue at a carboxyl terminus. In some embodiments, thelevel of antibodies comprising a lysine or an arginine residue at acarboxyl terminus relative to the sum of the level of antibodiescomprising a lysine or an arginine residue at a carboxyl terminus andthe level of antibodies not comprising a lysine or an arginine residueat a carboxyl terminus is about 0.1, about 0.2, about 0.3, about 0.4,about 0.5, about 0.6, about 0.7, about 0.8, about 0.9, or about 1.

In some embodiments, the target value is a level of heavy chains in thepopulation comprising a C-terminal lysine or arginine. In someembodiments, the target value is a level of heavy chains having aC-terminal lysine or arginine in the population of at least about 1%, atleast about 2%, at least about 3%, at least about 4%, at least about 5%,at least about 6%, at least about 7%, at least about 8%, at least about9%, at least about 10%, at least about 11%, at least about 12%, at leastabout 13%, at least about 14%, at least about 15%, at least about 16%,at least about 17%, at least about 18%, at least about 19%, at leastabout 20%, at least about 25%, at least about 30%, at least about 35%,at least about 40%, at least about 45%, at least about 50%, or more. Insome embodiments, the target value is a level of K1 lysine variantsand/or K2 lysine variants in the population. In some embodiments, thetarget value is a level of K1 lysine variants and/or K2 lysine variantsin the population of at least about 1%, at least about 2%, at leastabout 3%, at least about 4%, at least about 5%, at least about 6%, atleast about 7%, at least about 8%, at least about 9%, at least about10%, at least about 11%, at least about 12%, at least about 13%, atleast about 14%, at least about 15%, at least about 16%, at least about17%, at least about 18%, at least about 19%, at least about 20%, atleast about 25%, at least about 30%, at least about 35%, at least about40%, at least about 45%, at least about 50%, or more.

In some embodiments, the method further comprises measuring a level ofone or more of K0, K1, or K2 lysine variants in the population. In someembodiments, the method further comprises recording the level of one ormore of K0, K1, or K2 lysine variants in a print or computer-readablemedium, e.g., in a test report, Material Safety Data Sheet (MSDS) orCertificate of Testing or Certificate of Analysis (CofA).

In another aspect, the invention features a method of producing apopulation of recombinant antibodies, comprising: providing a targetvalue of C-terminal variants of a recombinant antibody, providing a hostcell comprising a nucleic acid encoding the recombinant antibody,culturing the host cell in a medium comprising about 0.1 g/L glucose toabout 10 g/L glucose under conditions in which the cell expresses apopulation of C-terminal variants of the encoded recombinant antibody;and isolating the population, wherein the population comprises theprovided target value of C-terminal variants of the recombinantantibody.

In some embodiments, the medium comprises glucose at a concentration ofabout 0.5 g/L to about 2 g/L. In some embodiments, the medium comprisesglucose at a concentration of about 0.1 g/L to about 10 g/L, e.g., about0.2 g/L, about 0.3 g/L, about 0.4 g/L, about 0.5 g/L, about 0.6 g/L,about 0.7 g/L, about 0.8 g/L, about 0.9 g/L, about 1 g/L, about 1.1 g/L,about 1.2 g/L, about 1.3 g/L, about 1.4 g/L, about 1.5 g/L, about 1.6g/L, about 1.7 g/L, about 1.8 g/L, about 1.9 g/L, about 2 g/L, about 2.1g/L, about 2.2. g/L, about 2.3 g/L, about 2.4 g/L, about 2.5 g/L, about2.6 g/L, about 2.7 g/L, about 2.8 g/L, about 2.9 g/L, about 3 g/L, about3.5 g/L, about 4 g/L, about 4.5 g/L, about 5 g/L, about 5.5 g/L, about 6g/L, about 6.5 g/L, about 7 g/L, about 7.5 g/L, about 8 g/L, about 8.5g/L, about 9 g/L, about 9.5 g/L, about 10 g/L, or more. In someembodiments, the glucose concentration is a controlled glucoseconcentration.

In some embodiments, the target value is a level of antibodiescomprising a lysine or an arginine residue at a carboxyl terminus. Insome embodiments, the target value is a level of antibodies comprising alysine or an arginine residue at a carboxyl terminus relative to a sumof a level of antibodies comprising a lysine or an arginine residue at acarboxyl terminus and a level of antibodies not comprising a lysine oran arginine residue at a carboxyl terminus. In some embodiments, thelevel of antibodies comprising a lysine or an arginine residue at acarboxyl terminus relative to the sum of the level of antibodiescomprising a lysine or an arginine residue at a carboxyl terminus andthe level of antibodies not comprising a lysine or an arginine residueat a carboxyl terminus is about 0.1, about 0.2, about 0.3, about 0.4,about 0.5, about 0.6, about 0.7, about 0.8, about 0.9, or about 1.

In some embodiments, the target value is a level of heavy chains in thepopulation comprising a C-terminal lysine or arginine. In someembodiments, the target value is a level of heavy chains having aC-terminal lysine or arginine in the population of at least about 1%, atleast about 2%, at least about 3%, at least about 4%, at least about 5%,at least about 6%, at least about 7%, at least about 8%, at least about9%, at least about 10%, at least about 11%, at least about 12%, at leastabout 13%, at least about 14%, at least about 15%, at least about 16%,at least about 17%, at least about 18%, at least about 19%, at leastabout 20%, at least about 25%, at least about 30%, at least about 35%,at least about 40%, at least about 45%, at least about 50%, or more. Insome embodiments, the target value is a level of K1 lysine variantsand/or K2 lysine variants in the population. In some embodiments, thetarget value is a level of K1 lysine variants and/or K2 lysine variantsin the population of at least about 1%, at least about 2%, at leastabout 3%, at least about 4%, at least about 5%, at least about 6%, atleast about 7%, at least about 8%, at least about 9%, at least about10%, at least about 11%, at least about 12%, at least about 13%, atleast about 14%, at least about 15%, at least about 16%, at least about17%, at least about 18%, at least about 19%, at least about 20%, atleast about 25%, at least about 30%, at least about 35%, at least about40%, at least about 45%, at least about 50%, or more.

In some embodiments, the method further comprises measuring a level ofone or more of K0, K1, or K2 lysine variants in the population. In someembodiments, the method further comprises recording the level of one ormore of K0, K1, or K2 lysine variants in a print or computer-readablemedium, e.g., in a test report, Material Safety Data Sheet (MSDS) orCertificate of Testing or Certificate of Analysis (CofA).

In another aspect, the invention features a method of producing apopulation of recombinant antibodies, comprising: providing a targetvalue of C-terminal variants of a recombinant antibody, providing a hostcell comprising a nucleic acid encoding the recombinant antibody,culturing the host cell in a medium comprising about 1 mM to about 50 mMNH₄Cl under conditions in which the cell expresses a population ofC-terminal variants of the encoded recombinant antibody; and isolatingthe population, wherein the population comprises the provided targetvalue of C-terminal variants of the recombinant antibody.

In some embodiments, the medium comprises a concentration of NH₄Cl ofabout 1 mM to about 30 mM, e.g., about 1 mM, about 2 mM, about 3 mM,about 4 mM, about 5 mM, about 6 mM, about 7 mM, about 8 mM, about 9 mM,about 10 mM, about 11 mM, about 12 mM, about 13 mM, about 14 mM, about15 mM, about 16 mM, about 17 mM, about 18 mM, about 19 mM, about 20 mM,about 25 mM, about 30 mM, about 40 mM, about 50 mM, or more.

In some embodiments, the target value is a level of antibodiescomprising a lysine or an arginine residue at a carboxyl terminus. Insome embodiments, the target value is a level of antibodies comprising alysine or an arginine residue at a carboxyl terminus relative to a sumof a level of antibodies comprising a lysine or an arginine residue at acarboxyl terminus and a level of antibodies not comprising a lysine oran arginine residue at a carboxyl terminus. In some embodiments, thelevel of antibodies comprising a lysine or an arginine residue at acarboxyl terminus relative to the sum of the level of antibodiescomprising a lysine or an arginine residue at a carboxyl terminus andthe level of antibodies not comprising a lysine or an arginine residueat a carboxyl terminus is about 0.1, about 0.2, about 0.3, about 0.4,about 0.5, about 0.6, about 0.7, about 0.8, about 0.9, or about 1.

In some embodiments, the target value is a level of heavy chains in thepopulation comprising a C-terminal lysine or arginine. In someembodiments, the target value is a level of heavy chains having aC-terminal lysine or arginine in the population of at least about 1%, atleast about 2%, at least about 3%, at least about 4%, at least about 5%,at least about 6%, at least about 7%, at least about 8%, at least about9%, at least about 10%, at least about 11%, at least about 12%, at leastabout 13%, at least about 14%, at least about 15%, at least about 16%,at least about 17%, at least about 18%, at least about 19%, at leastabout 20%, at least about 25%, at least about 30%, at least about 35%,at least about 40%, at least about 45%, at least about 50%, or more. Insome embodiments, the target value is a level of K1 lysine variantsand/or K2 lysine variants in the population. In some embodiments, thetarget value is a level of K1 lysine variants and/or K2 lysine variantsin the population of at least about 1%, at least about 2%, at leastabout 3%, at least about 4%, at least about 5%, at least about 6%, atleast about 7%, at least about 8%, at least about 9%, at least about10%, at least about 11%, at least about 12%, at least about 13%, atleast about 14%, at least about 15%, at least about 16%, at least about17%, at least about 18%, at least about 19%, at least about 20%, atleast about 25%, at least about 30%, at least about 35%, at least about40%, at least about 45%, at least about 50%, or more.

In some embodiments, the method further comprises measuring a level ofone or more of K0, K1, or K2 lysine variants in the population. In someembodiments, the method further comprises recording the level of one ormore of K0, K1, or K2 lysine variants in a print or computer-readablemedium, e.g., in a test report, Material Safety Data Sheet (MSDS) orCertificate of Testing or Certificate of Analysis (CofA).

In another aspect, the invention features a method of producing apopulation of recombinant antibodies, comprising: providing a targetvalue of C-terminal variants of a recombinant antibody, providing a hostcell comprising a nucleic acid encoding the recombinant antibody,culturing the host cell in a medium comprising about 10 μm to about 500μm chloroquine under conditions in which the cell expresses a populationof C-terminal variants of the encoded recombinant antibody; andisolating the population, wherein the population comprises the providedtarget value of C-terminal variants of the recombinant antibody.

In some embodiments, the medium comprises chloroquine at a concentrationof about 10 μM, about 20 μM, about 30 μM, about 40 μM, about 50 μM,about 60 μM, about 70 μM, about 80 μM, about 90 μM, about 100 μM, about110 μM, about 120 μM, about 130 μM, about 140 μM, about 150 μM, about160 μM, about 170 μM, about 180 μM, about 190 μM, about 200 μM about 210μM, about 220 μM, about 230 μM, about 250 μM, about 250 μM, about 260μM, about 270 μM, about 280 μM, about 290 μM, about 300 μM, about 310μM, about 320 μM, about 330 μM, about 340 μM, about 350 μM, about 360μM, about 370 μM, about 380 μM, about 390 μM, about 400 μM, about 410μM, about 420 μM, about 430 μM, about 440 μM, about 450 μM, about 460μM, about 470 μM, about 480 μM, about 490 μM, about 500 μM, or more.

In some embodiments, the target value is a level of antibodiescomprising a lysine or an arginine residue at a carboxyl terminus. Insome embodiments, the target value is a level of antibodies comprising alysine or an arginine residue at a carboxyl terminus relative to a sumof a level of antibodies comprising a lysine or an arginine residue at acarboxyl terminus and a level of antibodies not comprising a lysine oran arginine residue at a carboxyl terminus. In some embodiments, thelevel of antibodies comprising a lysine or an arginine residue at acarboxyl terminus relative to the sum of the level of antibodiescomprising a lysine or an arginine residue at a carboxyl terminus andthe level of antibodies not comprising a lysine or an arginine residueat a carboxyl terminus is about 0.1, about 0.2, about 0.3, about 0.4,about 0.5, about 0.6, about 0.7, about 0.8, about 0.9, or about 1.

In some embodiments, the target value is a level of heavy chains in thepopulation comprising a C-terminal lysine or arginine. In someembodiments, the target value is a level of heavy chains having aC-terminal lysine or arginine in the population of at least about 1%, atleast about 2%, at least about 3%, at least about 4%, at least about 5%,at least about 6%, at least about 7%, at least about 8%, at least about9%, at least about 10%, at least about 11%, at least about 12%, at leastabout 13%, at least about 14%, at least about 15%, at least about 16%,at least about 17%, at least about 18%, at least about 19%, at leastabout 20%, at least about 25%, at least about 30%, at least about 35%,at least about 40%, at least about 45%, at least about 50%, or more. Insome embodiments, the target value is a level of K1 lysine variantsand/or K2 lysine variants in the population. In some embodiments, thetarget value is a level of K1 lysine variants and/or K2 lysine variantsin the population of at least about 1%, at least about 2%, at leastabout 3%, at least about 4%, at least about 5%, at least about 6%, atleast about 7%, at least about 8%, at least about 9%, at least about10%, at least about 11%, at least about 12%, at least about 13%, atleast about 14%, at least about 15%, at least about 16%, at least about17%, at least about 18%, at least about 19%, at least about 20%, atleast about 25%, at least about 30%, at least about 35%, at least about40%, at least about 45%, at least about 50%, or more.

In some embodiments, the method further comprises measuring a level ofone or more of K0, K1, or K2 lysine variants in the population. In someembodiments, the method further comprises recording the level of one ormore of K0, K1, or K2 lysine variants in a print or computer-readablemedium, e.g., in a test report, Material Safety Data Sheet (MSDS) orCertificate of Testing or Certificate of Analysis (CofA).

In another aspect, the invention features a method of producing apopulation of recombinant antibodies, comprising: providing a targetvalue of C-terminal variants of a recombinant antibody, providing a hostcell comprising a nucleic acid encoding the recombinant antibody,culturing the host cell in a medium comprising about 5 mM to about 80 mMglutamine under conditions in which the cell expresses a population ofC-terminal variants of the encoded recombinant antibody; and isolatingthe population, wherein the population comprises the provided targetvalue of C-terminal variants of the recombinant antibody.

In some embodiments, the medium comprises glutamine at a concentrationof about 10 mM to about 30 mM. In other embodiments, the mediumcomprises glutamine at a concentration of about 5 mM, about 10 mM, about15 mM, about 20 mM, about 25 mM, about 30 mM, about 35 mM, about 40 mM,about 45 mM, about 50 mM, about 55 mM, about 60 mM, about 65 mM, about70 mM, about 75 mM, about 80 mM, or more.

In some embodiments, the target value is a level of antibodiescomprising a lysine or an arginine residue at a carboxyl terminus. Insome embodiments, the target value is a level of antibodies comprising alysine or an arginine residue at a carboxyl terminus relative to a sumof a level of antibodies comprising a lysine or an arginine residue at acarboxyl terminus and a level of antibodies not comprising a lysine oran arginine residue at a carboxyl terminus. In some embodiments, thelevel of antibodies comprising a lysine or an arginine residue at acarboxyl terminus relative to the sum of the level of antibodiescomprising a lysine or an arginine residue at a carboxyl terminus andthe level of antibodies not comprising a lysine or an arginine residueat a carboxyl terminus is about 0.1, about 0.2, about 0.3, about 0.4,about 0.5, about 0.6, about 0.7, about 0.8, about 0.9, or about 1.

In some embodiments, the target value is a level of heavy chains in thepopulation comprising a C-terminal lysine or arginine. In someembodiments, the target value is a level of heavy chains having aC-terminal lysine or arginine in the population of at least about 1%, atleast about 2%, at least about 3%, at least about 4%, at least about 5%,at least about 6%, at least about 7%, at least about 8%, at least about9%, at least about 10%, at least about 11%, at least about 12%, at leastabout 13%, at least about 14%, at least about 15%, at least about 16%,at least about 17%, at least about 18%, at least about 19%, at leastabout 20%, at least about 25%, at least about 30%, at least about 35%,at least about 40%, at least about 45%, at least about 50%, or more. Insome embodiments, the target value is a level of K1 lysine variantsand/or K2 lysine variants in the population. In some embodiments, thetarget value is a level of K1 lysine variants and/or K2 lysine variantsin the population of at least about 1%, at least about 2%, at leastabout 3%, at least about 4%, at least about 5%, at least about 6%, atleast about 7%, at least about 8%, at least about 9%, at least about10%, at least about 11%, at least about 12%, at least about 13%, atleast about 14%, at least about 15%, at least about 16%, at least about17%, at least about 18%, at least about 19%, at least about 20%, atleast about 25%, at least about 30%, at least about 35%, at least about40%, at least about 45%, at least about 50%, or more.

In some embodiments, the method further comprises measuring a level ofone or more of K0, K1, or K2 lysine variants in the population. In someembodiments, the method further comprises recording the level of one ormore of K0, K1, or K2 lysine variants in a print or computer-readablemedium, e.g., in a test report, Material Safety Data Sheet (MSDS) orCertificate of Testing or Certificate of Analysis (CofA).

In another aspect, the invention features a method producing arecombinant Fc-containing polypeptide, comprising: culturing a cell in amedium comprising about 1 g/L to about 50 g/L histidine under conditionsin which the cell expresses a population of the recombinant antibody;isolating the population; and measuring the level of one or more of K0,K1, or K2 lysine variants of the population. In some embodiments, theFc-containing polypeptide is an antibody.

In some embodiments, the medium comprises histidine at a concentrationof at least about 1.5 g/L, at least about 2 g/L, at least about 2.5 g/L,at least about 3 g/L, at least about 3.5 g/L, at least about 4 g/L, atleast about 4.5 g/L, at least about 5 g/L, at least about 5.5 g/L, atleast about 6 g/L, at least about 6.5 g/L, at least about 7 g/L, atleast about 7.5 g/L, at least about 8 g/L, at least about 8.5 g/L, atleast about 9 g/L, at least about 9.5 g/L, at least about 10 g/L, atleast about 10.5 g/L, at least about 11 g/L, at least about 11.5 g/L, atleast about 12 g/L, at least about 12.5 g/L, at least about 13 g/L, atleast about 13.5 g/L, at least about 14 g/L, at least about 14.5 g/L, atleast about 15 g/L, at least about 15.5 g/L, at least about 16 g/L, atleast about 16.5 g/L, at least about 17 g/L, at least about 17.5 g/L, atleast about 18 g/L, at least about 18.5 g/L, at least about 19 g/L, atleast about 19.5 g/L, at least about 20 g/L, at least about 25 g/L, atleast about 30 g/L, at least about 35 g/L, at least about 40 g/L, atleast about 45 g/L, at least about 50 g/L, or more

In some embodiments, the level of K1 lysine variants and/or K2 lysinevariants in the population is at least about 1%, at least about 2%, atleast about 3%, at least about 4%, at least about 5%, at least about 6%,at least about 7%, at least about 8%, at least about 9%, at least about10%, at least about 11%, at least about 12%, at least about 13%, atleast about 14%, at least about 15%, at least about 16%, at least about17%, at least about 18%, at least about 19%, at least about 20%, atleast about 25%, at least about 30%, at least about 35%, at least about40%, at least about 45%, at least about 50%, or more.

In some embodiments, the method further comprises recording the level ofK0, K1, and/or K2 lysine variants in a print or computer-readablemedium, e.g., in a test report, Material Safety Data Sheet (MSDS) orCertificate of Testing or Certificate of Analysis (CofA).

In another aspect, the invention features a method producing arecombinant Fc-containing polypeptide, comprising: culturing a cell in amedium comprising about 0.1 g/L to about 10 g/L glucose under conditionsin which the cell expresses a population of the recombinant antibody;isolating the population; and measuring the level of one or more of K0,K1, or K2 lysine variants of the population. In some embodiments, theFc-containing polypeptide is an antibody.

In some embodiments, the medium comprises glucose at a concentration ofabout 0.5 g/L to about 2 g/L. In some embodiments, the medium comprisesglucose at a concentration of about 0.1 g/L to about 10 g/L, e.g., about0.2 g/L, about 0.3 g/L, about 0.4 g/L, about 0.5 g/L, about 0.6 g/L,about 0.7 g/L, about 0.8 g/L, about 0.9 g/L, about 1 g/L, about 1.1 g/L,about 1.2 g/L, about 1.3 g/L, about 1.4 g/L, about 1.5 g/L, about 1.6g/L, about 1.7 g/L, about 1.8 g/L, about 1.9 g/L, about 2 g/L, about 2.1g/L, about 2.2. g/L, about 2.3 g/L, about 2.4 g/L, about 2.5 g/L, about2.6 g/L, about 2.7 g/L, about 2.8 g/L, about 2.9 g/L, about 3 g/L, about3.5 g/L, about 4 g/L, about 4.5 g/L, about 5 g/L, about 5.5 g/L, about 6g/L, about 6.5 g/L, about 7 g/L, about 7.5 g/L, about 8 g/L, about 8.5g/L, about 9 g/L, about 9.5 g/L, about 10 g/L, or more. In someembodiments, the glucose concentration is a controlled glucoseconcentration.

In some embodiments, the level of K1 lysine variants and/or K2 lysinevariants in the population is at least about 1%, at least about 2%, atleast about 3%, at least about 4%, at least about 5%, at least about 6%,at least about 7%, at least about 8%, at least about 9%, at least about10%, at least about 11%, at least about 12%, at least about 13%, atleast about 14%, at least about 15%, at least about 16%, at least about17%, at least about 18%, at least about 19%, at least about 20%, atleast about 25%, at least about 30%, at least about 35%, at least about40%, at least about 45%, at least about 50%, or more.

In some embodiments, the method further comprises recording the level ofK0, K1, and/or K2 lysine variants in a print or computer-readablemedium, e.g., in a test report, Material Safety Data Sheet (MSDS) orCertificate of Testing or Certificate of Analysis (CofA).

In another aspect, the invention features a method producing arecombinant Fc-containing polypeptide, comprising: culturing a cell in amedium comprising about 1 mM NH₄Cl to about 50 mM NH₄Cl under conditionsin which the cell expresses a population of the recombinant antibody;isolating the population; and measuring the level of one or more of K0,K1, or K2 lysine variants of the population. In some embodiments, theFc-containing polypeptide is an antibody.

In some embodiments, the medium comprises a concentration of NH₄Cl ofabout 1 mM to about 30 mM, e.g., about 1 mM, about 2 mM, about 3 mM,about 4 mM, about 5 mM, about 6 mM, about 7 mM, about 8 mM, about 9 mM,about 10 mM, about 11 mM, about 12 mM, about 13 mM, about 14 mM, about15 mM, about 16 mM, about 17 mM, about 18 mM, about 19 mM, about 20 mM,about 25 mM, about 30 mM, about 40 mM, about 50 mM, or more.

In some embodiments, the level of K1 lysine variants and/or K2 lysinevariants in the population is at least about 1%, at least about 2%, atleast about 3%, at least about 4%, at least about 5%, at least about 6%,at least about 7%, at least about 8%, at least about 9%, at least about10%, at least about 11%, at least about 12%, at least about 13%, atleast about 14%, at least about 15%, at least about 16%, at least about17%, at least about 18%, at least about 19%, at least about 20%, atleast about 25%, at least about 30%, at least about 35%, at least about40%, at least about 45%, at least about 50%, or more.

In some embodiments, the method further comprises recording the level ofK0, K1, and/or K2 lysine variants in a print or computer-readablemedium, e.g., in a test report, Material Safety Data Sheet (MSDS) orCertificate of Testing or Certificate of Analysis (CofA).

In another aspect, the invention features a method producing arecombinant Fc-containing polypeptide, comprising: culturing a cell in amedium comprising about 5 mM to about 80 mM glutamine under conditionsin which the cell expresses a population of the recombinant antibody;isolating the population; and measuring the level of one or more of K0,K1, or K2 lysine variants of the population. In some embodiments, theFc-containing polypeptide is an antibody.

In some embodiments, the medium comprises glutamine at a concentrationof about 10 mM to about 30 mM. In other embodiments, the mediumcomprises glutamine at a concentration of about 5 mM, about 10 mM, about15 mM, about 20 mM, about 25 mM, about 30 mM, about 35 mM, about 40 mM,about 45 mM, about 50 mM, about 55 mM, about 60 mM, about 65 mM, about70 mM, about 75 mM, about 80 mM, or more.

In some embodiments, the level of K1 lysine variants and/or K2 lysinevariants in the population is at least about 1%, at least about 2%, atleast about 3%, at least about 4%, at least about 5%, at least about 6%,at least about 7%, at least about 8%, at least about 9%, at least about10%, at least about 11%, at least about 12%, at least about 13%, atleast about 14%, at least about 15%, at least about 16%, at least about17%, at least about 18%, at least about 19%, at least about 20%, atleast about 25%, at least about 30%, at least about 35%, at least about40%, at least about 45%, at least about 50%, or more.

In some embodiments, the method further comprises recording the level ofK0, K1, and/or K2 lysine variants in a print or computer-readablemedium, e.g., in a test report, Material Safety Data Sheet (MSDS) orCertificate of Testing or Certificate of Analysis (CofA).

In another aspect, the invention features a method producing arecombinant Fc-containing polypeptide, comprising: culturing a cell in amedium comprising about 10 μM to about 500 μM chloroquine underconditions in which the cell expresses a population of the recombinantantibody; isolating the population; and measuring the level of one ormore of K0, K1, or K2 lysine variants of the population. In someembodiments, the Fc-containing polypeptide is an antibody.

In some embodiments, the medium comprises chloroquine at a concentrationof about 10 μM, about 20 μM, about 30 μM, about 40 μM, about 50 μM,about 60 μM, about 70 μM, about 80 μM, about 90 μM, about 100 μM, about110 μM, about 120 μM, about 130 μM, about 140 μM, about 150 μM, about160 μM, about 170 μM, about 180 μM, about 190 μM, about 200 μM, about210 μM, about 220 μM, about 230 μM, about 250 μM, about 250 μM, about260 μM, about 270 μM, about 280 μM, about 290 μM, about 300 μM, about310 μM, about 320 μM, about 330 μM, about 340 μM, about 350 μM, about360 μM, about 370 μM, about 380 μM, about 390 μM, about 400 μM, about410 μM, about 420 μM, about 430 μM, about 440 μM, about 450 μM, about460 μM, about 470 μM, about 480 μM, about 490 μM, about 500 μM, or more.

In some embodiments, the level of K1 lysine variants and/or K2 lysinevariants in the population is at least about 1%, at least about 2%, atleast about 3%, at least about 4%, at least about 5%, at least about 6%,at least about 7%, at least about 8%, at least about 9%, at least about10%, at least about 11%, at least about 12%, at least about 13%, atleast about 14%, at least about 15%, at least about 16%, at least about17%, at least about 18%, at least about 19%, at least about 20%, atleast about 25%, at least about 30%, at least about 35%, at least about40%, at least about 45%, at least about 50%, or more.

In some embodiments, the method further comprises recording the level ofK0, K1, and/or K2 lysine variants in a print or computer-readablemedium, e.g., in a test report, Material Safety Data Sheet (MSDS) orCertificate of Testing or Certificate of Analysis (CofA).

In another aspect, the invention features a method of producing apreparation of recombinant Fc-containing polypeptides, comprising:culturing cells in a medium comprising one or more of: (i) about 2 g/Lto about 50 g/L histidine; (ii) about 0.5 g/L glucose to about 2 g/Lglucose; (iii) about 2 mM to about 10 mM NH₄Cl; (iv) about 5 mM to about80 mM glutamine; and (v) about 10 μM to about 500 μM chloroquine; underconditions in which the cells express recombinant antibodies; andisolating the recombinant antibodies from the cells or the medium toproduce a preparation comprising a target value of K0, K1, and/or K2lysine variants of the recombinant Fc-containing polypeptides. In someembodiments, the Fc-containing polypeptides are antibodies.

In some embodiments, the target value is a level of Fc-containingpolypeptides comprising a lysine or an arginine residue at a carboxylterminus. In some embodiments, the target value is a level ofFc-containing polypeptides comprising a lysine or an arginine residue ata carboxyl terminus relative to a sum of a level of Fc-containingpolypeptides comprising a lysine or an arginine residue at a carboxylterminus and a level of Fc-containing polypeptides not comprising alysine or an arginine residue at a carboxyl terminus. In someembodiments, the level of Fc-containing polypeptides comprising a lysineor an arginine residue at a carboxyl terminus relative to the sum of thelevel of Fc-containing polypeptides comprising a lysine or an arginineresidue at a carboxyl terminus and the level of Fc-containingpolypeptides not comprising a lysine or an arginine residue at acarboxyl terminus is about 0.1, about 0.2, about 0.3, about 0.4, about0.5, about 0.6, about 0.7, about 0.8, about 0.9, or about 1.

In some embodiments, the target value is a level of heavy chains in thepopulation comprising a C-terminal lysine or arginine. In someembodiments, the target value is a level of heavy chains having aC-terminal lysine or arginine in the population of at least about 1%, atleast about 2%, at least about 3%, at least about 4%, at least about 5%,at least about 6%, at least about 7%, at least about 8%, at least about9%, at least about 10%, at least about 11%, at least about 12%, at leastabout 13%, at least about 14%, at least about 15%, at least about 16%,at least about 17%, at least about 18%, at least about 19%, at leastabout 20%, at least about 25%, at least about 30%, at least about 35%,at least about 40%, at least about 45%, at least about 50%, or more. Insome embodiments, the target value is a level of K1 lysine variantsand/or K2 lysine variants in the population. In some embodiments, thetarget value is a level of K1 lysine variants and/or K2 lysine variantsin the population of at least about 1%, at least about 2%, at leastabout 3%, at least about 4%, at least about 5%, at least about 6%, atleast about 7%, at least about 8%, at least about 9%, at least about10%, at least about 11%, at least about 12%, at least about 13%, atleast about 14%, at least about 15%, at least about 16%, at least about17%, at least about 18%, at least about 19%, at least about 20%, atleast about 25%, at least about 30%, at least about 35%, at least about40%, at least about 45%, at least about 50%, or more.

In some embodiments, the method further comprises measuring a level ofone or more of K0, K1, or K2 lysine variants in the population. In someembodiments, the method further comprises recording the level of one ormore of K0, K1, or K2 lysine variants in a print or computer-readablemedium, e.g., in a test report, Material Safety Data Sheet (MSDS) orCertificate of Testing or Certificate of Analysis (CofA).

In one aspect, the invention features a method of producing arecombinant polypeptide, comprising: culturing a cell in a mediumcomprising at least about 1 g/L lysine, at least about 1 g/L arginine,or at least 1 g/L of a combination of lysine and arginine, underconditions in which the cell expresses a recombinant polypeptide.

In some embodiments, the method further comprises isolating therecombinant polypeptide. In some embodiments, the method furthercomprises measuring the level of lysine and/or arginine residues at theC-terminus of the isolated recombinant polypeptide. In some embodiments,the method further comprises recording the level of lysine and/orarginine residues in a print or computer-readable medium, e.g., in atest report, Material Safety Data Sheet (MSDS) or Certificate of Testingor Certificate of Analysis (CofA).

In some embodiments, the recombinant polypeptide is a recombinantantibody or a recombinant Fc fusion protein.

In another aspect, the invention features a method of producing arecombinant antibody or recombinant Fc fusion protein, comprising:culturing a cell in a medium comprising at least about 1 g/L lysine, atleast about 1 g/L arginine, or at least 1 g/L of a combination of lysineand arginine, under conditions in which the cell expresses a recombinantantibody or a recombinant Fc fusion protein.

In some embodiments, the method further comprises isolating therecombinant antibody or the recombinant Fc fusion protein. In someembodiments, the method further comprises measuring a level of one ormore of K0, K1, or K2 lysine variants in a preparation of the isolatedrecombinant antibody or the recombinant fusion protein. In someembodiments, the method further comprises recording the level of one ormore of K0, K1, or K2 lysine residues in a print or computer-readablemedium, e.g., in a test report, Material Safety Data Sheet (MSDS) orCertificate of Testing or Certificate of Analysis (CofA).

In another aspect, the invention features a method of producing apreparation of recombinant antibodies, comprising: culturing cells in amedium comprising at least about 1 g/L lysine, at least about 1 g/Larginine, or at least 1 g/L of a combination of lysine and arginineunder conditions in which the cells express recombinant antibodies; andisolating the recombinant antibodies from the cells or the medium toproduce a preparation comprising a target value of K0, K1, and/or K2lysine variants.

In some embodiments, the method further comprises measuring the level ofK0, K1, and/or K2 lysine variants in the preparation. In someembodiments, the method further comprises recording the level of K0, K1,and/or K2 lysine variants in a print or computer-readable medium, e.g.,in a test report, Material Safety Data Sheet (MSDS) or Certificate ofTesting or Certificate of Analysis (CofA).

In another aspect, the invention features a method of producing apreparation of recombinant antibodies, comprising: culturing cells in amedium comprising at least about 1 g/L lysine, at least about 1 g/Larginine, or at least 1 g/L of a combination of lysine and arginineunder conditions in which the cells express recombinant antibodies; andisolating the recombinant antibodies from the cells or the medium toproduce a preparation comprising at least about 1% of K1 and/or K2lysine variants.

In some embodiments, the method further comprises measuring the level ofK0, K1 and/or K2 lysine variants and comparing them to a referencestandard (e.g., a product description in an FDA label, a Physician'sInsert, a USP monograph, or an EP monograph). In some embodiments, themethod includes recording the level of K0, K1 and/or K2 lysine variantsin a print or computer-readable medium, e.g., in a test report, MaterialSafety Data Sheet (MSDS) or Certificate of Testing or Certificate ofAnalysis (CofA).

In some embodiments, the method further comprises determining the levelof K1, and/or K2 lysine variants in the preparation. In someembodiments, the preparation comprises at least about 1%, at least about2%, at least about 3%, at least about 4%, at least about 5%, at leastabout 6%, at least about 7%, at least about 8%, at least about 9%, atleast about 10%, at least about 11%, at least about 12%, at least about13%, at least about 14%, at least about 15%, at least about 16%, atleast about 17%, at least about 18%, at least about 19%, at least about20%, at least about 25%, at least about 30%, at least about 35%, atleast about 40%, at least about 45%, at least about 50%, or more, of K1and/or K2 lysine variants.

In some embodiments, the method further comprises recording the level ofK0, K1, and/or K2 lysine variants in a print or computer-readablemedium, e.g., in a test report, Material Safety Data Sheet (MSDS) orCertificate of Testing or Certificate of Analysis (CofA).

In another aspect, the invention features a method of producing apreparation of recombinant antibodies having a target value of one ormore of K0, K1, or K2 lysine variants, comprising: culturing cells in amedium comprising lysine and/or arginine under conditions in which thecells express recombinant antibodies; measuring a level of one or moreof K0, K1, or K2 lysine variants in the culture; and isolating therecombinant antibodies from the cells or the medium to produce apreparation of the recombinant antibodies when the level of one or moreof K0, K1, or K2 lysine variants in the culture is a target value.

In some embodiments, the method further comprises recording the level ofK0, K1, and/or K2 lysine variants in a print or computer-readablemedium, e.g., in a test report, Material Safety Data Sheet (MSDS) orCertificate of Testing or Certificate of Analysis (CofA).

In another aspect, the invention features a method of decreasing a levelof K0 lysine variants and/or increasing a level of one or more of K1 orK2 lysine variants in a preparation of recombinant antibodies,comprising: culturing cells in a medium comprising an amount of lysine,arginine, and/or a combination of lysine and arginine that is more thanan amount of lysine, arginine, and/or a combination of lysine andarginine in a standard medium, wherein the cells are cultured underconditions in which the cells express recombinant antibodies; andisolating the recombinant antibodies, thereby decreasing the level of K0lysine variants and/or increasing the level of one or more of K1 or K2lysine variants in the preparation relative to a preparation ofrecombinant antibodies produced from cells cultured in a standardmedium.

In another aspect, the invention features a method of decreasing a levelof K0 lysine variants and/or increasing a level of one or more of K1 orK2 lysine variants in a preparation of recombinant antibodies,comprising: culturing cells in a medium comprising at least about 1 g/Llysine, at least about 1 g/L arginine, or at least 1 g/L of acombination of lysine and arginine under conditions in which the cellsexpress recombinant antibodies; and isolating the recombinantantibodies, thereby decreasing the level of K0 lysine variants and/orincreasing the level of one or more of K1 or K2 lysine variants in thepreparation relative to a preparation of recombinant antibodies notproduced using a medium comprising at least about 1 g/L lysine, at leastabout 1 g/L arginine, or at least 1 g/L of a combination of lysine andarginine.

In another aspect, the invention features a method of culturing cellsproducing a recombinant antibody, comprising: growing cells in a mediumcomprising at least about 1 g/L lysine, at least about 1 g/L arginine,or at least 1 g/L of a combination of lysine and arginine underconditions in which the cells express a recombinant antibody.

In some embodiments, the method further comprises monitoring a level ofone or more of K0, K1, or K2 lysine variants in the culture. In someembodiments, the method further comprises removing the cells from theculture when the level of one or more of K0, K1, or K2 lysine variantsreaches a target value.

In another aspect, the invention features a recombinant polypeptide,such as a recombinant antibody, produced by a method described herein.

In another aspect, the invention features a cell culture mediumcomprising at least about 1 g/L lysine, at least about 1 g/L arginine,or at least 1 g/L of a combination of lysine and arginine.

In another aspect, the invention features a cell culture comprising:cells expressing recombinant antibodies; and a medium comprising atleast about 1 g/L lysine, at least about 1 g/L arginine, or at least 1g/L of a combination of lysine and arginine.

In some embodiments, the culture comprises a target value of one or moreof K0, K1, or K2 lysine variants.

In some embodiments, the culture is a batch culture, a continuousculture, or a fed-batch culture.

In another aspect, the invention features a bioreactor comprising a cellculture described herein.

In some aspects described herein, the medium comprises lysine (e.g.,L-lysine), arginine (e.g., L-arginine), or a combination of lysine(e.g., L-lysine) and arginine (e.g., L-arginine), in an amount of atleast about 1.5 g/L, at least about 2 g/L, at least about 2.5 g/L, atleast about 3 g/L, at least about 3.5 g/L, at least about 4 g/L, atleast about 4.5 g/L, at least about 5 g/L, at least about 5.5 g/L, atleast about 6 g/L, at least about 6.5 g/L, at least about 7 g/L, atleast about 7.5 g/L, at least about 8 g/L, at least about 8.5 g/L, atleast about 9 g/L, at least about 9.5 g/L, at least about 10 g/L, atleast about 10.5 g/L, at least about 11 g/L, at least about 11.5 g/L, atleast about 12 g/L, at least about 12.5 g/L, at least about 13 g/L, atleast about 13.5 g/L, at least about 14 g/L, at least about 14.5 g/L, atleast about 15 g/L, at least about 15.5 g/L, at least about 16 g/L, atleast about 16.5 g/L, at least about 17 g/L, at least about 17.5 g/L, atleast about 18 g/L, at least about 18.5 g/L, at least about 19 g/L, atleast about 19.5 g/L, at least about 20 g/L, at least about 25 g/L, atleast about 30 g/L, at least about 35 g/L, at least about 40 g/L, atleast about 45 g/L, at least about 50 g/L, or more.

In other aspects, the medium comprises lysine (e.g., L-lysine), arginine(e.g., L-arginine), or a combination of lysine (e.g., L-lysine) andarginine (e.g., L-arginine), in an amount of at least about 1 mM, about2 mM, about 3 mM, about 4 mM, about 5 mM, about 6 mM, about 7 mM, about8 mM, about 9 mM, about 10 mM, about 11 mM, about 12 mM, about 13 mM,about 14 mM, about 15 mM, about 20 mM, about 25 mM, about 30 mM, about35 mM, about 40 mM, about 45 mM, about 50 mM, about 55 mM, about 60 mM,about 65 mM, about 70 mM, about 75 mM, about 80 mM, about 85 mM, about90 mM, about 95 mM, about 100 mM, about 125 mM, about 150 mM, about 200mM, about 250 mM, about 300 mM, about 350 mM, about 400 mM, about 450mM, about 500 mM, or more.

In another aspect, the invention features a method of increasing a levelof K0 lysine variants and/or decreasing a level of one or more of K1 orK2 lysine variants in a preparation of recombinant antibodies,comprising: culturing cells in a medium comprising an amount of lysine,arginine, and/or a combination of lysine and arginine that is less thanan amount of lysine, arginine, and/or a combination of lysine andarginine in a standard medium, wherein the cells are cultured underconditions in which the cells express recombinant antibodies; andisolating the recombinant antibodies, thereby increasing the level of K0lysine variants and/or decreasing the level of one or more of K1 or K2lysine variants in the preparation relative to a preparation ofrecombinant antibodies produced from cells cultured in a standardmedium.

In some aspects described herein, the method further comprisesmonitoring the amount of lysine, arginine, histidine, glucose, NH₄Cl,chloroquine, and/or glutamine in the medium during the culturing step,e.g., at least once, twice, three times or more during the culturingstep.

In some aspects described herein, the target value is a level set forthin a reference standard, such as a product specification or a qualitycriterion for a pharmaceutical preparation containing the recombinantantibody preparation. For example, the product specification is aproduct description in an FDA label, a Physician's Insert, a USPmonograph, or an EP monograph.

In particular embodiments, the target value is a level of K0, K1, and/orK2 lysine variants in a preparation of corresponding recombinantantibodies.

In another aspect, the invention features a method of producing apreparation of recombinant antibodies, comprising: culturing cells in amedium comprising one or more of: (i) about 2 g/L to about 50 g/Lhistidine; (ii) about 0.5 g/L glucose to about 2 g/L glucose; (iii)about 2 mM to about 10 mM NH₄Cl; (iv) about 5 mM to about 80 mMglutamine; and (v) about 10 μM to about 500 μM chloroquine; underconditions in which the cells express recombinant antibodies; isolatingthe recombinant antibodies from the cells or the medium to produce apreparation; measuring the level of K0, K1, and/or K2 lysine variants ofthe recombinant antibodies in the preparation; and formulating thepreparation the preparation into a drug product if the level of K0, K1,and/or K2 lysine variants is a target value.

In some embodiments, the target value is a level of antibodiescomprising a lysine or an arginine residue at a carboxyl terminus. Insome embodiments, the target value is a level of antibodies comprising alysine or an arginine residue at a carboxyl terminus relative to a sumof a level of antibodies comprising a lysine or an arginine residue at acarboxyl terminus and a level of antibodies not comprising a lysine oran arginine residue at a carboxyl terminus. In some embodiments, thelevel of antibodies comprising a lysine or an arginine residue at acarboxyl terminus relative to the sum of the level of antibodiescomprising a lysine or an arginine residue at a carboxyl terminus andthe level of antibodies not comprising a lysine or an arginine residueat a carboxyl terminus is about 0.1, about 0.2, about 0.3, about 0.4,about 0.5, about 0.6, about 0.7, about 0.8, about 0.9, or about 1.

In some embodiments, the target value is a level of heavy chains in thepopulation comprising a C-terminal lysine or arginine. In someembodiments, the target value is a level of heavy chains having aC-terminal lysine or arginine in the population of at least about 1%, atleast about 2%, at least about 3%, at least about 4%, at least about 5%,at least about 6%, at least about 7%, at least about 8%, at least about9%, at least about 10%, at least about 11%, at least about 12%, at leastabout 13%, at least about 14%, at least about 15%, at least about 16%,at least about 17%, at least about 18%, at least about 19%, at leastabout 20%, at least about 25%, at least about 30%, at least about 35%,at least about 40%, at least about 45%, at least about 50%, or more. Insome embodiments, the target value is a level of K1 lysine variantsand/or K2 lysine variants in the population. In some embodiments, thetarget value is a level of K1 lysine variants and/or K2 lysine variantsin the population of at least about 1%, at least about 2%, at leastabout 3%, at least about 4%, at least about 5%, at least about 6%, atleast about 7%, at least about 8%, at least about 9%, at least about10%, at least about 11%, at least about 12%, at least about 13%, atleast about 14%, at least about 15%, at least about 16%, at least about17%, at least about 18%, at least about 19%, at least about 20%, atleast about 25%, at least about 30%, at least about 35%, at least about40%, at least about 45%, at least about 50%, or more.

In another aspect, the invention features a method of manufacturing apharmaceutical antibody preparation, comprising: providing a targetvalue of C-terminal lysine variants for a therapeutic recombinantantibody, providing a host cell comprising a nucleic acid encoding alight chain and a heavy chain of a recombinant antibody, culturing thehost cell under conditions (i) in which the cell expresses the encodedlight chain and heavy chain to form the recombinant antibody and (ii)which increase the intracellular pH of the cell, isolating a populationof the therapeutic recombinant antibody from the cell or cell culture,and formulating the isolated population into a pharmaceutical drugproduct if the population comprises the provided target value ofC-terminal lysine variants, thereby manufacturing a pharmaceuticalantibody preparation.

In some embodiments, the target value of C-terminal lysine variants is apreselected level of C-terminal lysine-containing heavy chains relativeto the total heavy chains in the population. In some embodiments, thetarget value of C-terminal lysine variants is a preselected level of K1lysine variants and/or K2 lysine variants in the population.

In some aspects described herein, the conditions in which cells (e.g.,mammalian cells) express recombinant polypeptides or recombinantantibodies comprise (i) a medium having a pH of about 6, about 6.5,about 6.6, about 6.7, about 6.8, about 6.9, about 7, about 7.1, about7.2, about 7.3, about 7.4, about 7.5, or about 8; (ii) a temperature ofabout 25° C., about 26° C., about 27° C., about 28° C., about 29° C.,about 30° C., about 31° C., about 32° C., about 33° C., about 34° C.,about 35° C., about 36° C., about 37° C., about 38° C., about 39° C., orabout 40° C.; and/or (iii) a culture volume of about 100 mL, about 200mL, about 300 mL, about 400 mL, about 500 mL, about 600 mL, about 700mL, about 800 mL, about 900 mL, about 1 L, about 2 L, about 3 L, about 5L, about 10 L, about 20 L, about 30 L, about 40 L, about 50 L, about 100L, about 200 L, about 300 L, about 400 L, about 500 L, about 600 L,about 700 L, about 800 L, about 900 L, about 1000 L, or more.

In some aspects described herein, the cells are mammalian cells. Incertain embodiments, the mammalian cells are CHO, Vero, BHK, HeLa, COS,MDCK, or HEK-293 cells.

In some aspects described herein, the recombinant antibody is abciximab,adalimumab, alemtuzumab, basiliximab, bevacizumab, cetuximab,certolizumab, daclizumab, eculizumab, efalizumab, gemtuzumab,ibritumomab, infliximab, muromonab, natalizumab, omalizumab,palivizumab, panitumumab, ranibizumab, rituximab, tositumomab, ortrastuzumab.

In some aspects described herein, the polypeptide is a fusion protein.In certain embodiments, the fusion protein is alefacept, abatacept,etanercept, rilonacept, or denileukin diftitox.

BRIEF DESCRIPTION OF THE DRAWINGS

The present teachings described herein will be more fully understoodfrom the following description of various illustrative embodiments, whenread together with the accompanying drawings. It should be understoodthat the drawings described below are for illustration purposes only andare not intended to limit the scope of the present teachings in any way.

FIG. 1 is a graphic representation of the levels of K1 and K2 lysineresidues in a preparation of a model antibody from cells grown in acontrol process, in a process supplemented with 10 g/L lysine, in aprocess supplemented with 10 g/L arginine, compared to levels of K1 andK2 lysine residues in a preparation of Humira®.

DETAILED DESCRIPTION

The inventors have discovered that polypeptides (e.g., antibodies)having targeted levels of carboxyl terminal (C-terminal) lysine orarginine residues can be produced from cells cultured in a medium havingsufficient levels of lysine, arginine, and/or agents that changeintracellular pH. Surprisingly, culturing the cells under suchconditions does not affect cell growth, cell viability, or titer. Thepresent disclosure encompasses polypeptides (e.g., antibodies) havingtargeted levels of C-terminal lysine and/or arginine residues, methodsof making such polypeptides (e.g., antibodies), and methods of usingsuch polypeptides (e.g., antibodies).

DEFINITIONS

As used herein, “purified” (or “isolated”) refers to a nucleic acidsequence (e.g., a polynucleotide) or an amino acid sequence (e.g., apolypeptide) that is substantially free of other components. In someembodiments, a purified polynucleotide or purified polypeptide isremoved or separated from other components present in its naturalenvironment. For example, an isolated polypeptide is one that isseparated from other components of a cell in which it was produced(e.g., the endoplasmic reticulum or cytoplasmic proteins and RNA). Anisolated polynucleotide is one that is separated from other nuclearcomponents (e.g., histones) and/or from upstream or downstream nucleicacid sequences. An isolated nucleic acid sequence or amino acid sequencecan be at least 60% free, or at least 75% free, or at least 90% free, orat least 95% free from other components present in natural environmentof the indicated nucleic acid sequence or amino acid sequence.

As used herein, “polynucleotide” (or “nucleotide sequence” or “nucleicacid molecule”) refers to an oligonucleotide, nucleotide, orpolynucleotide, and fragments or portions thereof, and to DNA and RNA ofgenomic or synthetic origin, which may be single- or double-stranded,and represent the sense or anti-sense strand.

As used herein, “polypeptide” (or “amino acid sequence” or “protein”)refers to an oligopeptide, peptide, polypeptide, or protein sequence,and fragments or portions thereof, and to naturally occurring orsynthetic molecules. “Amino acid sequence” and like terms, such as“polypeptide” or “protein”, are not meant to limit the indicated aminoacid sequence to the complete, native amino acid sequence associatedwith the recited protein molecule.

The articles “a” and “an” are used herein to refer to one or to morethan one (i.e., to at least one) of the grammatical object of thearticle. By way of example, “an element” means one element or more thanone element.

The term “pharmaceutically effective amount” or “therapeuticallyeffective amount” refers to an amount (e.g., dose) effective in treatinga patient, having a disorder or condition described herein. It is alsoto be understood herein that a “pharmaceutically effective amount” maybe interpreted as an amount giving a desired therapeutic effect, eithertaken in one dose or in any dosage or route, taken alone or incombination with other therapeutic agents.

The term “treatment” or “treating”, as used herein, refers toadministering a therapy in an amount, manner, and/or mode effective toimprove a condition, symptom, or parameter associated with a disorder orcondition or to prevent or reduce progression of a disorder orcondition, to a degree detectable to one skilled in the art. Aneffective amount, manner, or mode can vary depending on the subject andmay be tailored to the subject.

The term “subject”, as used herein, means any subject for whomdiagnosis, prognosis, or therapy is desired. For example, a subject canbe a mammal, e.g., a human or non-human primate (such as an ape, monkey,orangutan, or chimpanzee), a dog, cat, guinea pig, rabbit, rat, mouse,horse, cattle, or cow.

As used herein, the term “antibody” refers to a polypeptide thatincludes at least one immunoglobulin variable region, e.g., an aminoacid sequence that provides an immunoglobulin variable domain orimmunoglobulin variable domain sequence. For example, an antibody caninclude a heavy (H) chain variable region (abbreviated herein as VH),and a light (L) chain variable region (abbreviated herein as VL). Inanother example, an antibody includes two heavy (H) chain variableregions and two light (L) chain variable regions. The term “antibody”encompasses antigen-binding fragments of antibodies (e.g., single chainantibodies, Fab, F(ab′)₂, Fd, Fv, and dAb fragments) as well as completeantibodies, e.g., intact immunoglobulins of types IgA, IgG, IgE, IgD,IgM (as well as subtypes thereof). The light chains of theimmunoglobulin can be of types kappa or lambda. In some embodiments, anantibody includes an Fc region. In some embodiments, an antibody is atherapeutic antibody.

As used herein, the term “constant region” refers to a polypeptide thatcorresponds to, or is derived from, one or more constant regionimmunoglobulin domains of an antibody. A constant region can include anyor all of the following immunoglobulin domains: a CH1 domain, a hingeregion, a CH2 domain, a CH3 domain (derived from an IgA, IgD, IgG, IgE,or IgM), and a CH4 domain (derived from an IgE or IgM).

As used herein, the term “Fc region” refers to a polypeptide comprisingthe constant region of an antibody excluding the first constant regionimmunoglobulin domain. “Fc region” refers to the last two constantregion immunoglobulin domains of IgA, IgD, and IgG, and the last threeconstant region immunoglobulin domains of IgE and IgM, and may alsoinclude part or all of the flexible hinge N-terminal to these domains.For IgG, “Fc region” comprises immunoglobulin domains Cgamma2 (Cγ2) andCgamma3 (Cγ3) and the lower part of the hinge between Cgamma1 (Cγ1) andCγ2. Although the boundaries of the Fc region may vary, the human IgGheavy chain Fc region is usually defined to comprise residues startingat T223 or C226 or P230, to its carboxyl-terminus, wherein the numberingis according to the EU index as in Kabat et al. (1991, NIH Publication91-3242, National Technical Information Services, Springfield, Va.). ForIgA, the Fc region comprises immunoglobulin domains Calpha2 (Cα2) andCalpha3 (Cα3) and the lower part of the hinge between Calpha1 (Cα1) andCα2.

As used herein, the term “Fc-containing polypeptide” refers to apolypeptide comprising a dimer of two polypeptides containing Fcregions, such as an intact antibody or Fc-receptor fusion protein.

As used herein, the term “Fc region variant” refers to an analog of anFc region that possesses one or more Fc-mediated activities describedherein. This term includes Fc regions comprising one or more amino acidmodifications relative to a wild type or naturally existing Fc region.For example, variant Fc regions can possess at least about 50% homology,at least about 75% homology, at least about 80% homology, at least about85%, homology, at least about 90% homology, at least about 95% homology,or more, with a naturally existing Fc region. Fc region variants alsoinclude Fc regions comprising one or more amino acid residues added toor deleted from the N- or C-terminus of a wild type Fc region.

As used herein, the terms “coupled”, “linked”, “joined”, “fused”, and“fusion” are used interchangeably. These terms refer to the joiningtogether of two more elements or components by whatever means, includingchemical conjugation or recombinant means.

The terms “overexpress,” “overexpression” or “overexpressed”interchangeably refer to a protein that is transcribed and translated orto a nucleic acid that is transcribed at a detectably greater level thanthe level in a control cell. The term includes expression due totranscription, post transcriptional processing, translation,post-translational processing, cellular localization (e.g., organelle,cytoplasm, nucleus, cell surface), and RNA and protein stability, ascompared to a control cell. Overexpression can be detected usingconventional techniques, e.g., for detecting mRNA (i.e., RT-PCR, PCR,hybridization) or proteins (i.e., ELISA, immunohistochemicaltechniques). Overexpression can be expression in an amount greater thanabout 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% or more compared tothe expression in a control cell. In certain instances, overexpressionis 1-fold, 2-fold, 3-fold, 4-fold, or more, higher level oftranscription or translation compared to expression in a control cell.

As used herein, “C-terminal variants” of a polypeptide (e.g., anantibody or an Fc-containing polypeptide) are versions of suchpolypeptide (e.g., antibody or Fc-containing polypeptide) that differ inamino acid sequence only by the presence or absence of a particularamino acid residue at their carboxyl termini. In some embodiments,“C-terminal variants” of a polypeptide differ only by the presence orabsence of a lysine or arginine residue at their C-termini In someembodiments, “C-terminal variants” of an antibody or Fc-containingpolypeptide are K0 lysine variants, K1 lysine variants, K2 lysinevariants, R0 arginine variants, R1 arginine variants, and/or R2 argininevariants.

As used herein, “K0 lysine variant”, “K1 lysine variant”, and “K2 lysinevariant” of an antibody or an Fc-containing polypeptide are versions ofsuch antibody or Fc-containing polypeptide (e.g., polypeptide includingan Fc dimer, e.g., an intact antibody) that differ in amino acidsequence only by the presence or absence of a lysine residue at theirheavy chain carboxyl termini. A “K0 lysine variant” does not have alysine residue at either heavy chain C-terminus. A “K1 lysine variant”has a lysine residue at one heavy chain C-terminus. A “K2 lysinevariant” has a lysine residue at each heavy chain C-terminus.

As used herein, “R0 arginine variant”, “R1 arginine variant”, and “R2arginine variant” of an antibody or Fc-containing polypeptide areversions of such antibody or Fc-containing polypeptide (e.g.,polypeptide including an Fc dimer, e.g., an intact antibody) that differin amino acid sequence only by the presence or absence of an arginineresidue at their heavy chain carboxyl termini. An “R0 arginine variant”does not have an arginine residue at either heavy chain C-terminus. An“R1 arginine variant” has an arginine residue at one heavy chainC-terminus. An “R2 arginine variant” has an arginine residue at eachheavy chain C-terminus.

As used herein, “preparation” in the context of polypeptides, fusionproteins, antibodies, or Fc-containing polypeptides, refers to a set ofindividual polypeptides, fusion proteins, antibodies, or Fc-containingpolypeptides, respectively, each of which comprises a particular aminoacid sequence. In some embodiments, a preparation includes C-terminalvariants of such polypeptides, fusion proteins, antibodies, orFc-containing polypeptides. In some embodiments, individualpolypeptides, fusion proteins, antibodies, or Fc-containing polypeptideswithin a preparation have identical amino acid sequences but differ inthe presence or absence of a particular amino acid residue (e.g., alysine residue or an arginine residue) at a carboxyl terminus. Forexample, a “preparation of antibodies” refers to a set of antibodiesthat includes one or more C-terminal variants. In some embodiments, a“preparation of antibodies” includes one or more of K0 lysine variants,K1 lysine variants, K2 lysine variants, R0 arginine variants, R1arginine variants, and R2 arginine variants.

As used herein, a “target value” is a predetermined level of one or moreC-terminal variants, such as K0 lysine variants, K1 lysine variants, K2lysine variants, R0 arginine variants, R1 arginine variants, and/or R2arginine variants. In some embodiments, a target value is an absolutevalue. In some embodiments, a target value is a relative value. In someembodiments, a target value is a level of C-terminal lysine-containingpolypeptide relative to the sum of levels of C-terminallysine-containing polypeptides and C-terminal lysine-free polypeptides,e.g., detected in a population of such polypeptides.

In some embodiments, a “target value” is a level of heavy chains in apreparation of an Fc-containing polypeptide (e.g., antibody) comprisinga C-terminal lysine or arginine. In some embodiments, a target value isa level of heavy chains having a C-terminal lysine or arginine in such apreparation of greater than about 5%, greater than about 10%, greaterthan about 15%, or greater than about 20%, or more.

In some embodiments, a “target value” is a level of K1 lysine variantsand/or K2 lysine variants in a preparation of isolated recombinantFc-containing polypeptides (e.g., antibodies). In some embodiments, atarget value is a level of K1 lysine variants and/or K2 lysine variantsin such a preparation of greater than about 5%, greater than about 10%,greater than about 15%, or greater than about 20%, or more.

As used herein, a “corresponding recombinant antibody” means arecombinant antibody that is the same recombinant antibody as aparticular antibody but produced by a different recombinant method. Forexample, a corresponding recombinant antibody can be a bioequivalent ora biosimilar antibody.

Carboxypeptidases

C-terminal lysine or arginine residues are often absent in proteinsisolated from mammalian cell cultures, even though their presence may beexpected on the basis of gene sequence. This discrepancy often resultsfrom the activity of one or more carboxypeptidases, The carboxypeptidasefamily of exopeptidases constitute a diverse group of enzymes thathydrolyze carboxyl-terminal amide bonds in polypeptides.Carboxypeptidase B is a zinc-containing exopeptidase catalyzing ahydrolytic release of the C-terminal basic amino acid residues ofarginine and lysine from peptides and proteins. Other mammaliancarboxypeptidases besides carboxypeptidase B that specifically removeterminal basic amino acids include carboxypeptidase H (also known asenkephalin convertase or carboxypeptidase E (Frickler et al., J. Mol.Endocrinol., 3: 666-673 (1989); Manser et al., Biochem. J., 267: 517-525(1990)), carboxypeptidase M (EC 3.4.17.12) (Tan et al., J. Biol. Chem.,264: 13165-13170 (1989)), carboxypeptidase N (Tan et al., J. Biol.Chem., 265: 13-19 (1990)), carboxypeptidase U, carboxypeptidase D,carboxypeptidase R, carboxypeptidase Z, and SCPEP1 (Reznik et al., CMLS,Cell. Mol. Life. Sci. 58:1790-1804 (2001)).

Agents for C-Terminal Modification of Polypeptides

In some embodiments, an activator or an inhibitor of a carboxypeptidaseis used to produce targeted levels of C-terminal variants ofpolypeptides (e.g., antibodies). Activators and inhibitors of variouscarboxypeptidases are known. Exemplary, nonlimiting activators forcarboxypeptidase E and/or M include Co²⁺, Zn²⁺, NiCl₂, Na₂SO₄, KCl,NaNO₃, NaCl, and KNO₃. Inhibitors for these enzymes include, but are notlimited to, 1,10-phenanthroline; 4-chloromercuriphenylsulfonate;aminopropylmercaptosuccinic acid; arginine; CdCl₂ (Cd compounds); CuCl₂;EDTA; FeSO₄; Guanidinoethylmercaptosuccinic acid (GEMSA); HgCl₂;Leu-enkephalin; luteinizing hormone-releasing hormone; lysine;Met-enkephalin; Met-Enkephalin-Arg-Gly-Leu; oxytocin;p-chloromercuriphenyl sulfonate; Substance P; sulfhydryl reagents;thyrotropin-releasing hormone; [Leu5]Enkephalin-Arg6;[Met5]Enkephalin-Arg6; and Met-Enkephalin-Arg6-Phe7. Particularinhibitors useful in the present disclosure are lysine and arginine,e.g., L-lysine, D-lysine, L-arginine, D-arginine, and derivatives andsalts thereof.

In some embodiments, an agent capable of directly or indirectlymodifying pH (e.g., intracellular pH of a cell described herein) (“pHmodifying agent”) is used to produce targeted levels of C-terminalvariants of polypeptides (e.g., antibodies). Without wishing to be boundby theory, it is believed that modifying, e.g., increasing,intracellular pH can modify, e.g., increase, levels of C-terminal lysineand/or arginine residues on polypeptides (e.g., antibodies) by directlyor indirectly modifying one or more mechanisms involved in regulation ofC-terminal lysine and/or arginine residues. Such a mechanism caninclude, or can be independent of, carboxypeptidase activity. Forexample, without wishing to be bound by theory, it is believed thatincreasing pH of intracellular compartments involved in the secretorypathway can increase levels of C-terminal lysine and/or arginineresidues of a polypeptide (e.g., antibody). Accordingly, in someembodiments, a pH modifying agent that can increase pH in one or morecompartments of secretory pathway of a cell (e.g., ER, Golgi, secretoryvesicle) is used to increase levels of C-terminal lysine and/or arginineresidues of a polypeptide (e.g., an antibody), e.g., to a targetedlevel.

Such pH modifying agents include, without limitation, ammonium salts(e.g., ammonium nitrate, ammonium carbonate, ammonium acetate, ammoniummethanesulfonate, ammonium tolylsulfonate, ammonium chloride, ammoniumbromide, ammonium sulfate, or ammonium phosphate), basic amino acids(e.g., lysine, arginine, and/or histidine), polar amino acids (e.g.,glutamine, asparagine, serine, or threonine), glucose, chloroquine,methylamine, tributylamine, benzylamine, and triethylamine.

In some embodiments, an activator or an inhibitor of a carboxypeptidaseis also a pH modifying agent. For example, lysine and/or arginine caninhibit a carboxypeptidase and can also increase intracellular pH.Without wishing to be bound by theory, such agents can increase levelsof C-terminal lysine and/or arginine residues of a polypeptide (e.g.,antibody), to a targeted level, by inhibiting a carboxypeptidase, byincreasing intracellular pH, or both.

As described herein, carboxypeptidase activators, carboxypeptidaseinhibitors, and/or pH modifying agents, are used to produce targetedlevels of C-terminal variants of polypeptides (e.g., antibodies). Inparticular instances, K0 lysine variants, K1 lysine variants, K2 lysinevariants, R0 arginine variants, R1 arginine variants, and/or R2 argininevariants of antibodies are produced. For example, carboxypeptidaseinhibitors (e.g., arginine and/or lysine), carboxypeptidase activators,and/or pH modifying agents are used to prepare targeted levels of K0lysine variants, K1 lysine variants, K2 lysine variants, R0 argininevariants, R1 arginine variants, and/or R2 arginine variants.

Cells

Any host cell that can be used to express a polypeptide of interest(e.g., an antibody) can be used in the methods described herein. Thecells can contain a recombinant nucleic acid sequence, e.g., a gene,that encodes a polypeptide of interest (e.g., an antibody). For example,useful cells can express a recombinant polypeptide. Recombinantexpression of a gene encoding a polypeptide, can include construction ofan expression vector containing a polynucleotide that encodes thepolypeptide. Once a polynucleotide has been obtained, a vector for theproduction of the polypeptide can be produced by recombinant DNAtechnology using techniques known in the art. Known methods can be usedto construct expression vectors containing polypeptide coding sequencesand appropriate transcriptional and translational control signals. Thesemethods include, for example, in vitro recombinant DNA techniques,synthetic techniques, and in vivo genetic recombination.

An expression vector can be transferred to a host cell by conventionaltechniques, and the transfected cells can then cultured by conventionaltechniques to produce polypeptide. A variety of host expression vectorsystems can be used (see, e.g., U.S. Pat. No. 5,807,715). Suchhost-expression systems can be used to produce polypeptides (e.g.,antibodies) and, where desired, subsequently purified. Such hostexpression systems include, but are not limited to, yeast (e.g.,Saccharomyces and Pichia) transformed with recombinant yeast expressionvectors containing polypeptide coding sequences; insect cell systemsinfected with recombinant virus expression vectors (e.g., baculovirus)containing polypeptide coding sequences; plant cell systems infectedwith recombinant virus expression vectors (e.g., cauliflower mosaicvirus, CaMV; tobacco mosaic virus, TMV) or transformed with recombinantplasmid expression vectors (e.g., Ti plasmid) containing polypeptidecoding sequences; or mammalian cell systems (e.g., COS, CHO, BHK, 293,NS0, and 3T3 cells) harboring recombinant expression constructscontaining promoters derived from the genome of mammalian cells (e.g.,metallothionein promoter) or from mammalian viruses (e.g., theadenovirus late promoter; the vaccinia virus 7.5K promoter).

For expression in mammalian host cells, viral-based expression systemscan be utilized (see, e.g., Logan et al., 1984, Proc. Natl. Acad. Sci.USA 8:355-359). The efficiency of expression can be enhanced by theinclusion of appropriate transcription enhancer elements, transcriptionterminators, etc. (see, e.g., Bittner et al., 1987, Methods in Enzymol.153:516-544).

In addition, a host cell strain can be chosen that modulates theexpression of the inserted sequences, or modifies and processes the geneproduct in the specific fashion desired. Different host cells havecharacteristic and specific mechanisms for the post-translationalprocessing and modification of proteins and gene products. Appropriatecell lines or host systems can be chosen to ensure the correctmodification and processing of the polypeptide (e.g., antibody)expressed. Such cells include, for example, established mammalian celllines and insect cell lines, animal cells, fungal cells, and yeastcells. Mammalian host cells include, but are not limited to, CHO, Vero,BHK, HeLa, COS, MDCK, HEK-293, NIH-3T3, W138, BT483, Hs578T, HTB2, BT20,T47D, NS0 (a murine myeloma cell line that does not endogenously produceany immunoglobulin chains), CRL7O3O, HsS78Bst cells, PER.C6, SP2/0-Ag14,and hybridoma cells. Additional, nonlimiting examples of animal ormammalian host cells include Chinese hamster ovary cells (CHO), such asCHO-K1 (ATCC CCL-61), DG44 (Chasin et al., 1986. Som. Cell Molec.Genet., 12:555-556; and Kolkekar et al., 1997, Biochem.,36:10901-10909), CHO-DXB11 (G. Urlaub and L. A. Chasin, 1980 Proc. Natl.Acad. Sci., 77: 4216-4220. L. H. Graf, and L. A. Chasin 1982, Molec.Cell. Biol., 2: 93-96). CHO-K1 Tet-On cell line (Clontech), CHOdesignated ECACC 85050302 (CAMR, Salisbury, Wiltshire, UK), CHO clone 13(GEIMG, Genova, IT), CHO clone B (GEIMG, Genova, IT), CHO-K1/SFdesignated ECACC 93061607 (CAMR, Salisbury, Wiltshire, UK), RR-CHOK1designated ECACC 92052129 (CAMR, Salisbury, Wiltshire, UK),dihydrofolate reductase negative CHO cells (CH)/-Urlaub and Chasin,1980, Proc, Natl. Acad. Sci. USA, 77:4216), and dp12.CHO cells (U.S.Pat. No. 5,721,121); monkey kidney CV1 cells transformed by SV40 (COScells, COS-7, ATCC CRL-1651); human embryonic kidney cells (e.g., 293cells, or 293 cells subcloned for growth in suspension culture, Grahamet al., 1977, J. Gen. Virol., 36:59); baby hamster kidney cells (BHK,ATCC CCL-10); monkey kidney cells (CV1. ATCC CCL-70); African greenmonkey kidney cells (VERO-76, ATCC CRL-1587; VERO, ATCC CCL-81); mousesertoli cells (TM4, Mather, 1980, Biol. Reprod., 23:243-251); humancervical carcinoma cells (HELA, ATCC CCL-2); canine kidney cells (MDCK,ATCC CCL-34); human lung cells (W138, ATCC CCL-75); human hepatoma cells(HEP-G2, HB 8065); mouse mammary tumor cells (MMT 060562, ATCC CCL-51);buffalo rat liver cells (BRL 3A, ATCC CRL-1442); TR1 cells (Mather,1982, Ann. NY Acad. Sci., 383:44-68); MCR 5 cells; and FS4 cells.

For long-term, high-yield production of recombinant proteins, host cellsare engineered to stably express a polypeptide (e.g., antibody). Hostcells can be transformed with DNA controlled by appropriate expressioncontrol elements known in the art, including promoter, enhancer,sequences, transcription terminators, polyadenylation sites, andselectable markers. Methods commonly known in the art of recombinant DNAtechnology can be used to select a desired recombinant clone.

Once a polypeptide described herein (e.g., an antibody described herein)has been produced by recombinant expression, it may be purified by anymethod known in the art for purification, for example, by chromatography(e.g., ion exchange, affinity, and sizing column chromatography),centrifugation, differential solubility, or by any other standardtechnique for the purification of proteins. For example, an antibody canbe isolated and purified by appropriately selecting and combiningaffinity columns such as Protein A column with chromatography columns,filtration, ultra filtration, salting-out and dialysis procedures (seeAntibodies: A Laboratory Manual, Ed Harlow, David Lane, Cold SpringHarbor Laboratory, 1988). Further, as described herein, a polypeptide(e.g., an antibody) can be fused to heterologous polypeptide sequencesto facilitate purification. Polypeptides having desired sugar chains canbe separated with a lectin column by methods known in the art (see,e.g., WO 02/30954).

In accordance with the present disclosure, there may be employedconventional molecular biology, microbiology, and recombinant DNAtechniques within the skill of the art. Such techniques are described inthe literature (see, e.g., Sambrook, Fritsch & Maniatis, MolecularCloning: A Laboratory Manual, Second Edition (1989) Cold Spring HarborLaboratory Press, Cold Spring Harbor, N.Y.; DNA Cloning: A PracticalApproach, Volumes I and II (D. N. Glover ed. 1985); OligonucleotideSynthesis (M. J. Gait ed. 1984); Nucleic Acid Hybridization (B. D. Hames& S. J. Higgins eds. (1985)); Transcription And Translation (B. D. Hames& S. J. Higgins, eds. (1984)); Animal Cell Culture (R. I. Freshney, ed.(1986)); Immobilized Cells and Enzymes (IRL Press, (1986)); B. Perbal, APractical Guide To Molecular Cloning (1984); F. M. Ausubel et al.(eds.), Current Protocols in Molecular Biology, John Wiley & Sons, Inc.(1994).

Culture Methods

In general, targeted levels of C-terminal variants of polypeptides(e.g., antibodies), can be produced by cells cultured in media thatcontains one or more carboxypeptidase activators, carboxypeptidaseinhibitors, and/or pH modifying agents. For example, for producing apreparation of C-terminal variants of a polypeptide (e.g., antibody)having a reduced level of C-terminal lysine and/or arginine residues,cells expressing such polypeptides can be cultured in a medium thatincludes an elevated level of a carboxypeptidase activator, a reducedlevel of a carboxypeptidase inhibitor (e.g., arginine or lysine), and/orthat includes an agent that reduces intracellular pH. In someembodiments for producing a preparation of C-terminal variants ofpolypeptides (e.g., antibodies) having a higher level of C-terminallysine and/or arginine residues, cells expressing such polypeptides canbe cultured in a medium that contains an elevated level of acarboxypeptidase inhibitor (e.g., arginine or lysine), a reduced levelof a carboxypeptidase activator, and/or that includes an agent thatincreases intracellular pH.

As used herein, an “elevated level” of a component means a higherconcentration of a component than is present in a standard medium,and/or that is present in a medium in which a polypeptide is produced.In some embodiments, a component is not present in a standard medium,and an “elevated level” is any amount of such component. A medium caninclude an elevated level of a component initially (i.e., at the startof a culture), or a starting medium can be supplemented with a componentto achieve an elevated level of the component at a particular time ortimes during culturing. For example, the starting medium can include atleast about 2 g/L arginine, at least about 2 g/L lysine, or at leastabout 2 g/L of a combination of arginine and lysine.

As used herein, a “reduced level” of a component means a lowerconcentration of a component than is present in a standard medium,and/or that is present in a medium in which a polypeptide is produced. Amedium can include a reduced level of a component initially (i.e., atthe start of a culture), a starting medium can be diluted at aparticular time or times during culturing to reduce the level of acomponent, or a starting medium can be replaced with a medium having areduced level of a component at a particular time or times duringculturing.

In some embodiments, a polypeptide (e.g., antibody) preparation havingtargeted values of C-terminal variants is produced by culturing a cellexpressing the polypeptide (e.g., antibody) under conditions thatincrease intracellular pH of the cell, e.g., that increase pH of one ormore secretory compartments of the cell described herein. IntracellularpH can be measured using known methods, e.g., by using a pH-sensitivegreen fluorescent protein (see, e.g., Tomkins et al., Am. J. Phys. CellPhysiol. 283:C429-37 (2002); Blackmore et al., J. Physol. 531:605-617(2001); Miesenbock et al., Nature 394:192-195 (1998)). In someembodiments, intracellular pH is increased using a pH modulating agent,e.g., an agent described herein. In some embodiments, intracellular pH(e.g., pH of a secretory compartment) is increased by at least about10%, at least about 20%, at least about 30%, at least about 40%, atleast about 50%, at least about 60%, at least about 70%, at least about80%, at least about 90%, at least about 100%, or more. In someembodiments, intracellular pH (e.g., pH of a secretory compartment) isincreased by a value of at least about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6,0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1,2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, or more.

In some embodiments, a polypeptide (e.g., antibody) preparation havingtargeted values of C-terminal variants is produced by culturing a cellexpressing the polypeptide (e.g., antibody) in a medium having anelevated level of an ammonium salt (e.g., NH₄Cl). In some embodiments, amedium contains NH₄Cl at a concentration of about 1 mM to about 30 mM,e.g., about 1 mM, about 2 mM, about 3 mM, about 4 mM, about 5 mM, about6 mM, about 7 mM, about 8 mM, about 9 mM, about 10 mM, about 11 mM,about 12 mM, about 13 mM, about 14 mM, about 15 mM, about 16 mM, about17 mM, about 18 mM, about 19 mM, about 20 mM, about 25 mM, about 30 mM,about 40 mM, about 50 mM, or more.

In some embodiments, a polypeptide (e.g., antibody) preparation havingtargeted values of C-terminal variants is produced by culturing a cellexpressing the polypeptide (e.g., antibody) in a medium having anelevated level of chloroquine. In some embodiments, a medium containschloroquine at a concentration of about 10 μM to about 500 μM, e.g.,about 10 μM, about 20 μM, about 30 μM, about 40 μM, about 50 μM, about60 μM, about 70 μM, about 80 μM, about 90 μM, about 100 μM, about 110μM, about 120 μM, about 130 μM, about 140 μM, about 150 μM, about 160μM, about 170 μM, about 180 μM, about 190 μM, about 200 μM, about 210μM, about 220 μM, about 230 μM, about 250 μM, about 250 μM, about 260μM, about 270 μM, about 280 μM, about 290 μM, about 300 μM, about 310μM, about 320 μM, about 330 μM, about 340 μM, about 350 μM, about 360μM, about 370 μM, about 380 μM, about 390 μM, about 400 μM, about 410μM, about 420 μM, about 430 μM, about 440 μM, about 450 μM, about 460μM, about 470 μM, about 480 μM, about 490 μM, about 500 μM, or more.

In some embodiments, a polypeptide (e.g., antibody) preparation havingtargeted values of C-terminal variants of such polypeptide (e.g.,antibody) is produced by culturing a cell expressing the polypeptide(e.g., antibody) in a medium having an elevated level of methylamine,tributylamine, benzylamine, and/or triethylamine. In some embodiments, amedium contains methylamine, tributylamine, benzylamine, triethylamine,or a combination thereof, at a concentration of about 10 μM to about 3mM, e.g., about 10 μM, about 50 μM, about 100 μM, about 150 μM, about200 μM, about 250 μM, about 300 μM, about 350 μM, about 400 μM, about450 μM, about 500 μM, about 550 μM, about 600 μM, about 650 μM, about750 μM, about 800 μM, about 850 μM, about 900 μM, about 950 μM, about 1mM, about 1.25 mM, about 1.5 mM, about 1.75 Mm, about 2 mM, about 2.25mM, about 2.5 mM, about 2.75 mM, about 3 mM, or more.

In some embodiments, a polypeptide (e.g., antibody) preparation havingtargeted values of C-terminal variants is produced by culturing a cellexpressing the polypeptide (e.g., antibody) in a medium having anelevated level glucose. In some embodiments, a medium contains glucoseat a concentration of about 0.1 g/L to about 10 g/L, e.g., about 0.2g/L, about 0.3 g/L, about 0.4 g/L, about 0.5 g/L, about 0.6 g/L, about0.7 g/L, about 0.8 g/L, about 0.9 g/L, about 1 g/L, about 1.1 g/L, about1.2 g/L, about 1.3 g/L, about 1.4 g/L, about 1.5 g/L, about 1.6 g/L,about 1.7 g/L, about 1.8 g/L, about 1.9 g/L, about 2 g/L, about 2.1 g/L,about 2.2. g/L, about 2.3 g/L, about 2.4 g/L, about 2.5 g/L, about 2.6g/L, about 2.7 g/L, about 2.8 g/L, about 2.9 g/L, about 3 g/L, about 3.5g/L, about 4 g/L, about 4.5 g/L, about 5 g/L, about 5.5 g/L, about 6g/L, about 6.5 g/L, about 7 g/L, about 7.5 g/L, about 8 g/L, about 8.5g/L, about 9 g/L, about 9.5 g/L, about 10 g/L, or more.

In some embodiments, a polypeptide (e.g., antibody) preparation havingtargeted values of C-terminal variants is produced by culturing a cellexpressing the polypeptide (e.g., antibody) in a medium having anelevated level of histidine, lysine, arginine, or a combination ofhistidine, lysine, and/or arginine. In some embodiments, a mediumcontains histidine, lysine, arginine, or a combination of histidine,lysine, and/or arginine, at a concentration of about 1 g/L to about 50g/L, for example, at least about 1 g/L, at least about 1.5 g/L, at leastabout 2 g/L, at least about 2.5 g/L, at least about 3 g/L, at leastabout 3.5 g/L, at least about 4 g/L, at least about 4.5 g/L, at leastabout 5 g/L, at least about 5.5 g/L, at least about 6 g/L, at leastabout 6.5 g/L, at least about 7 g/L, at least about 7.5 g/L, at leastabout 8 g/L, at least about 8.5 g/L, at least about 9 g/L, at leastabout 9.5 g/L, at least about 10 g/L, at least about 10.5 g/L, at leastabout 11 g/L, at least about 11.5 g/L, at least about 12 g/L, at leastabout 12.5 g/L, at least about 13 g/L, at least about 13.5 g/L, at leastabout 14 g/L, at least about 14.5 g/L, at least about 15 g/L, at leastabout 15.5 g/L, at least about 16 g/L, at least about 16.5 g/L, at leastabout 17 g/L, at least about 17.5 g/L, at least about 18 g/L, at leastabout 18.5 g/L, at least about 19 g/L, at least about 19.5 g/L, at leastabout 20 g/L, at least about 25 g/L, at least about 30 g/L, at leastabout 35 g/L, at least about 40 g/L, at least about 45 g/L, at leastabout 50 g/L, or more.

In some embodiments, a polypeptide (e.g., antibody) preparation havingtargeted values of C-terminal variants is produced by culturing a cellexpressing the polypeptide (e.g., antibody) in a medium having anelevated level of glutamine. In some embodiments, a medium containsglutamine at a concentration of about 5 mM to about 80 mM, e.g., about 5mM, about 10 mM, about 15 mM, about 20 mM, about 25 mM, about 30 mM,about 35 mM, about 40 mM, about 45 mM, about 50 mM, about 55 mM, about60 mM, about 65 mM, about 70 mM, about 75 mM, about 80 mM, or more.

Cells can be cultured in a variety of cell culture media known in theart, which are modified according to the disclosure to include one ormore carboxypeptidase activators, one or more carboxypeptidaseinhibitors, and/or one or more pH modifying agents (e.g., at an elevatedor reduced level) described herein. Cell culture medium is understood bythose of skill in the art to refer to a nutrient solution in whichcells, such as animal or mammalian cells, are grown. A cell culturemedium generally includes one or more of the following components: anenergy source (e.g., a carbohydrate such as glucose); amino acids;vitamins; lipids or free fatty acids; and trace elements, e.g.,inorganic compounds or naturally occurring elements in the micromolarrange. Cell culture medium can also contain additional components, suchas hormones and other growth factors (e.g., insulin, transferrin,epidermal growth factor, serum, and the like); salts (e.g., calcium,magnesium and phosphate); buffers (e.g., HEPES); nucleosides and bases(e.g., adenosine, thymidine, hypoxanthine); antibiotics (e.g.,gentamycin); and cell protective agents (e.g., a Pluronic polyol(Pluronic F68)).

Media that has been prepared or commercially available can be modifiedaccording to the present disclosure for utilization in the methodsdescribed herein. Nonlimiting examples of such media include MinimalEssential Medium (MEM, Sigma, St. Louis, Mo.); Ham's F10 Medium (Sigma);Dulbecco's Modified Eagles Medium (DMEM, Sigma); RPM I-1640 Medium(Sigma); HyClone cell culture medium (HyClone, Logan, Utah); Power CHO2(Lonza Inc., Allendale, N.J.); and chemically-defined (CD) media, whichare formulated for particular cell types, e.g., CD-CHO Medium(Invitrogen, Carlsbad, Calif.). Culture medium suitable for theparticular cells being cultured can be determined by a person ofordinary skill in the art without undue experimentation.

Cell culture conditions (including pH, O₂, CO₂, and temperature)suitable for cellular production of polypeptides described herein (e.g.,antibodies) are those that are known in the art, such as conditions forbatch, continuous, or fed-batch culturing of cells. For example, pH ofcell culture medium is generally maintained at about 6.8 to about 7.6.

In general, cell culture methods are classified as batch culture,continuous culture, and fed-batch culture. Any of these culture methodscan be used to grow cells that produce targeted levels of C-terminalvariants.

In batch culture, a small amount of seed culture solution is added to amedium and cells are grown without any addition of a new medium ordischarge of the culture solution during the culture. For the productionof targeted levels of C-terminal variants using batch culture, themedium comprises an elevated level or a reduced level of one or morecarboxypeptidase activator(s), one or more carboxypeptidaseinhibitor(s), and/or one or more a pH modifying agents from an initialstage of the cell culture.

In some embodiments, a polypeptide (e.g., antibody) preparation havingtargeted values of C-terminal variants is produced by batch culture ofcells expressing the polypeptide in a medium having at least about 2 g/Larginine, at least about 2 g/L lysine, at least about 2 g/L ofhistidine, at least about 2 g/L of a combination of arginine, lysineand/or histidine, at least about 5 mM NH₄Cl, about 10 μM to about 500 μMchloroquine, about 10 mM to about 30 mM glutamine, and/or about 0.5 g/Lto about 2 g/L glucose.

Continuous culture is a culture method in which a medium is added anddischarged continuously during the culture. This continuous methodincludes perfusion culture. For example, in the production of targetedlevels of C-terminal variants using continuous culture, the medium addedduring the culture can have an elevated level or a reduced level of oneor more carboxypeptidase activator(s), one or more carboxypeptidaseinhibitor(s), and/or one or more pH modifying agents. In certainmethods, the initial culture medium does not include an elevated levelor a reduced level of one or more carboxypeptidase activator(s), one ormore carboxypeptidase inhibitor(s), and/or one or more pH modifyingagents, but at a particular time point during the continuous culture(such as during production phase), the medium added during the cultureis elevated or reduced in the level of one or more carboxypeptidaseactivator(s), one or more carboxypeptidase inhibitor(s), and/or one ormore pH modifying agents.

In some embodiments, a polypeptide (e.g., antibody) preparation havingtargeted values of C-terminal variants is produced by continuous cultureof cells expressing the polypeptide in a medium having at least about 2g/L arginine, at least about 2 g/L lysine, at least about 2 g/L ofhistidine, at least about 2 g/L of a combination of arginine, lysineand/or histidine, at least about 5 mM NH₄Cl, about 10 μM to about 500 μMchloroquine, about 10 mM to about 30 mM glutamine, and/or about 0.5 g/Lto about 2 g/L glucose.

Fed-batch culture is a method between batch culture and continuousculture. In a fed-batch culture, a medium is fed continuously orsequentially during the culture, but unlike the continuous culture,discharge of the culture solution is not carried out during the culture.For example, for the production of targeted levels of C-terminalvariants using fed-batch culture, the medium added during the culturecan have an elevated level or a reduced level of one or morecarboxypeptidase activators, one or more carboxypeptidase inhibitors,and/or one or more pH modifying agents.

In some embodiments, a polypeptide (e.g., antibody) preparation havingtargeted values of C-terminal variants is produced by adding medium to afed batch culture of cells expressing the polypeptide sufficient toachieve at least about 2 g/L arginine, at least about 2 g/L lysine, atleast about 2 g/L of histidine, at least about 2 g/L of a combination ofarginine, lysine and/or histidine, at least about 5 mM NH₄Cl, about 10μM to about 500 μM chloroquine, about 10 mM to about 30 mM glutamine,and/or about 0.5 g/L to about 2 g/L glucose, in the culture medium.

According to the present disclosure, cell culture can be carried outunder conditions for the large or small scale production of polypeptides(e.g., antibodies), using culture vessels and/or culture apparatusesthat are conventionally employed for animal or mammalian cell culture.For example, tissue culture dishes, T-flasks, shaker flasks, and spinnerflasks can be used on a laboratory scale. For culturing on a largerscale (e.g., 500 L, 5000 L, or more), a fluidized bed bioreactor, ahollow fiber bioreactor, a roller bottle culture, or a stirred tankbioreactor system can be used (e.g., as described in U.S. Pat. Nos.7,541,164 and 7,332,303).

In particular methods, the level of C-terminal variants in a preparationof polypeptides (e.g., antibodies) is monitored during a particular cellculture, thereby allowing adjustment (e.g., increasing or decreasing theamount of one or more carboxypeptidase inhibitors, one or morecarboxypeptidase activators, and/or one or more pH modifying agents inthe culture) or possibly termination of the culture in order, forexample, to achieve a target level of C-terminal variants.

Polypeptides

The methods described herein can be used to produce any polypeptide ofinterest, such as an antibody, an Fc-containing polypeptide, and/or afusion protein.

The basic structure of an IgG antibody consists of two identical lightpolypeptide chains and two identical heavy polypeptide chains linkedtogether by disulfide bonds. The first domain located at the aminoterminus of each chain is variable in amino acid sequence, providing theantibody binding specificities found in each individual antibody. Theseare known as variable heavy (VH) and variable light (VL) regions. Theother domains of each chain are relatively invariant in amino acidsequence and are known as constant heavy (CH) and constant light (CL)regions. For an IgG antibody, the light chain includes one variableregion (VL) and one constant region (CL). An IgG heavy chain includes avariable region (VH), a first constant region (CH1), a hinge region, asecond constant region (CH2), and a third constant region (CH3). In IgEand IgM antibodies, the heavy chain includes an additional constantregion (CH4).

The nucleic acid sequences encoding antibodies and Fc-containingpolypeptides typically encode a lysine residue at the C-terminus of theheavy chains. C-terminal lysines, however, are often absent, or arepresent at reduced levels, in antibodies and Fc-containing polypeptidesisolated from mammalian cell cultures. In some embodiments, the presentmethods can increase the amount of lysine residues on antibodies orFc-containing polypeptides in an antibody preparation or a preparationof Fc-containing polypeptides. As used herein, “K0” means an antibody orFc-containing polypeptide not having a lysine residue on either heavychain C-terminus. As used herein, “K1” means an antibody orFc-containing polypeptide having a lysine residue on one heavy chainC-terminus. As used herein, “K2” means an antibody or Fc-containingpolypeptide having a lysine residue on each heavy chain C-terminus.

Antibodies can include, for example, monoclonal antibodies, polyclonalantibodies, multispecific antibodies, human antibodies, humanizedantibodies, camelized antibodies, chimeric antibodies, single-chain Fvs(scFv), disulfide-linked Fvs (sdFv), and anti-idiotypic (anti-Id)antibodies, and antigen-binding fragments of any of the above.Antibodies can be of any type (e.g., IgG, IgE, IgM, IgD, IgA and IgY),class (e.g., IgG1, IgG2, IgG3, IgG4, IgA1 and IgA2) or subclass.

The term “Fc fragment”, as used herein, refers to one or more fragmentsof an Fc region that retains an Fc function and/or activity, such asbinding to an Fc receptor. Examples of such fragments include fragmentsthat include an N-linked glycosylation site of an Fc region (e.g., anAsn297 of an IgG heavy chain or homologous sites of other antibodyisotypes), such as a CH2 domain. The term “antigen binding fragment” ofan antibody, as used herein, refers to one or more fragments of anantibody that retain the ability to specifically bind to an antigen.Examples of binding fragments encompassed within the term “antigenbinding fragment” of an antibody include a Fab fragment, a F(ab′)₂fragment, a Fd fragment, a Fv fragment, a scFv fragment, a dAb fragment(Ward et al., (1989) Nature 341:544-546), and an isolatedcomplementarity determining region (CDR). These antibody fragments canbe obtained using conventional techniques known to those with skill inthe art, and the fragments can be screened for utility in the samemanner as are intact antibodies.

Antibodies or fragments of the compositions and methods described hereincan be produced by any method known in the art for the synthesis ofantibodies (see, e.g., Harlow et al., Antibodies: A Laboratory Manual,(Cold Spring Harbor Laboratory Press, 2nd ed. 1988); Brinkman et al.,1995, J. Immunol. Methods 182:41-50; WO 92/22324; WO 98/46645). Chimericantibodies can be produced using the methods described in, e.g.,Morrison, 1985. Science 229:1202, and humanized antibodies by methodsdescribed in, e.g., U.S. Pat. No. 6,180,370.

Additional antibodies of the compositions and methods described hereinare bispecific antibodies and multivalent antibodies, as described in,e.g., Segal et al., J. Immunol. Meth. 248:1-6 (2001); and Tutt et al. J.Immunol. 147: 60 (1991).

Fc-containing polypeptides include, without limitation, fusion proteins,e.g., Fc regions or Fc fragments conjugated or fused to one or moreheterologous moieties. Heterologous moieties include, but are notlimited to, peptides, polypeptides, proteins, fusion proteins, nucleicacid molecules, small molecules, mimetic agents, synthetic drugs,inorganic molecules, and organic molecules. In some instances, anFc-containing polypeptide is or includes a fusion protein comprising apeptide, polypeptide, protein scaffold, scFv, dsFv, diabody, Tandab, oran antibody mimetic fused to an Fc region, such as a glycosylated Fcregion. The fusion protein can include a linker region connecting the Fcregion to the heterologous moiety (see, e.g., Hallewell et al. (1989),J. Biol. Chem. 264, 5260-5268; Alfthan et al. (1995) Protein Eng.8:725-731).

In some instances, an Fc-containing polypeptide is or includes an Fcregion conjugated to a heterologous polypeptide of at least 10, at least20, at least 30, at least 40, at least 50, at least 60, at least 70, atleast 80, at least 90 or at least 100 amino acids. In some instances, anFc-containing polypeptide is or includes an Fc region (or an Fcfragment) conjugated to a marker sequence, such as a peptide tofacilitate purification. A particular marker amino acid sequence is ahexa-histidine peptide, such as the tag provided in a pQE vector(QIAGEN, Inc., 9259 Eton Avenue, Chatsworth, Calif., 91311). Otherpeptide tags useful for purification include, but are not limited to,the hemagglutinin “HA” tag, which corresponds to an epitope derived fromthe influenza hemagglutinin protein (Wilson et al., 1984, Cell 37:767)and the “Flag” tag.

In other instances, an Fc-containing polypeptide is or includes an Fcregion conjugated to a diagnostic or detectable agent. SuchFc-containing polypeptides can be useful for monitoring or prognosingthe development or progression of disease or disorder as part of aclinical testing procedure, such as determining the efficacy of aparticular therapy. Such diagnosis and detection can be accomplished bycoupling the glycoprotein to detectable substances including, but notlimited to, various enzymes, such as but not limited to horseradishperoxidase, alkaline phosphatase, beta-galactosidase, oracetylcholinesterase; prosthetic groups, such as, but not limited to,streptavidin/biotin and avidin/biotin; fluorescent materials, such as,but not limited to, umbelliferone, fluorescein, fluoresceinisothiocynate, rhodamine, dichlorotriazinylamine fluorescein, dansylchloride or phycoerythrin; luminescent materials, such as, but notlimited to, luminol; bioluminescent materials, such as but not limitedto, luciferase, luciferin, and aequorin; radioactive materials, such asbut not limited to iodine (¹³¹I, ¹²⁵I, ¹²³I), carbon (¹⁴C), sulfur(³⁵S), tritium (³H), indium (¹¹⁵In, ¹¹³In, ¹¹²In, ¹¹¹In), technetium(⁹⁹Tc), thallium (²⁰¹Ti) gallium (⁶⁸Ga, ⁶⁷Ga), palladium (¹⁰³Pd),molybdenum (⁹⁹Mo), xenon (¹³³Xe), fluorine (¹⁸F), ¹⁵³Sm, ¹⁷⁷Lu, ¹⁵³Gd,¹⁵⁹Gd, ¹⁴⁹Pm, ¹⁴⁰La, ¹⁶⁹Yb, ¹⁷⁵Yb, ¹⁶⁶Ho, ⁹⁰Y, ⁴⁷Sc, ¹⁸⁶Re, ¹⁸⁸Re,¹⁴²Pr, ¹⁰⁵Rh ⁹⁷Ru, ⁶⁸Ge, ⁵⁷Co, ⁶⁵Zn, ⁸⁵Sr, ³²P, ⁵¹Cr, ⁵⁴Mn, ⁷⁵Se, ¹¹³Sn,and ¹¹⁷Sn; positron emitting metals using various positron emissiontomographies, non-radioactive paramagnetic metal ions, and moleculesthat are radiolabelled or conjugated to specific radioisotopes.

Techniques for conjugating therapeutic moieties to antibodies and/orFc-containing polypeptides are well known (see, e.g., Arnon et al.,“Monoclonal Antibodies For Immunotargeting Of Drugs In Cancer Therapy”,in Monoclonal Antibodies and Cancer Therapy, Reisfeld et al. (eds.), pp.243-56. (Alan R. Liss, Inc. 1985); Hellstrom et al., “Antibodies ForDrug Delivery”, in Controlled Drug Delivery (2nd Ed.), Robinson et al.(eds.), pp. 623-53 (Marcel Dekker, Inc. 1987)).

Nonlimiting, exemplary polypeptides that can be produced using themethods described herein include abatacept (Orencia®, Bristol-MyersSquibb), abciximab (ReoPro®, Roche), adalimumab (Humira®, Bristol-MyersSquibb), alefacept (Amevive®, Astellas Pharma), alemtuzumab (Campath®,Genzyme/Bayer), basiliximab (Simulect®, Novartis), bevacizumab(Avastin®, Roche), certolizumab (CIMZIA®, UCB, Brussels, Belgium),cetuximab (Erbitux®, Merck-Serono), daclizumab (Zenapax®, Hoffmann-LaRoche), denileukin diftitox (Ontak®, Eisai), eculizumab (Soliris®,Alexion Pharmaceuticals), efalizumab (Raptiva®, Genentech), etanercept(Enbrel®, Amgen-Pfizer), gemtuzumab (Mylotarg®, Pfizer), ibritumomab(Zevalin®, Spectrum Pharmaceuticals), infliximab (Remicadea Centocor),muromonab (Orthoclone OKT3®, Janssen-Cilag), natalizumab (Tysabri®,Biogen Idec, Elan), omalizumab (Xolair®, Novartis), palivizumab(Synagis®, MedImmune), panitumumab (Vectibix®, Amgen), ranibizumab(Lucentis®, Genentech), rilonacept (Arcalyst®, RegeneronPharmaceuticals), rituximab (MabThera®, Roche), tositumomab (Bexxar®,GlaxoSmithKline), and trastuzumab (Herceptin®, Roche).

A recombinant polypeptide described herein (e.g., an antibody) can beincorporated into a pharmaceutical composition. Such a pharmaceuticalcomposition is useful in the prevention and/or treatment of diseases.Pharmaceutical compositions comprising a polypeptide (e.g., an antibody)can be formulated by methods known to those skilled in the art. Thepharmaceutical composition can be administered parenterally in the formof an injectable formulation comprising a sterile solution or suspensionin water or another pharmaceutically acceptable liquid. For example, thepharmaceutical composition can be formulated by suitably combining thepolypeptide with pharmaceutically acceptable vehicles or media, such assterile water and physiological saline, vegetable oil, emulsifier,suspension agent, surfactant, stabilizer, flavoring excipient, diluent,vehicle, preservative, binder, followed by mixing in a unit dose formrequired for generally accepted pharmaceutical practices. The amount ofactive ingredient included in the pharmaceutical preparations is suchthat a suitable dose within the designated range is provided.

Route of administration can be parenteral, for example, administrationby injection, transnasal administration, transpulmonary administration,or transcutaneous administration. Administration can be systemic orlocal by intravenous injection, intramuscular injection, intraperitonealinjection, subcutaneous injection.

A suitable means of administration can be selected based on the age andcondition of the patient. A single dose of the pharmaceuticalcomposition containing a polypeptide (e.g., antibody) can be selectedfrom a range of 0.001 mg/kg of body weight to 1000 mg/kg of body weight.On the other hand, a dose can be selected in the range of 0.001 mg/kg ofbody weight to 100000 mg/kg of body weight, but the present disclosureis not limited to such ranges. The dose and method of administrationvaries depending on the weight, age, condition, and the like of thepatient, and can be suitably selected as needed by those skilled in theart.

In other instances, a recombinant polypeptide (e.g., antibody) can beused to screen for disease or for agents that can treat or preventdisease.

Methods of Assaying Levels of C-Terminal Variants and PolypeptideActivity

The level of C-terminal variants of a reference polypeptide (e.g., areference antibody) can be assayed by known methods (see, e.g., Dick etal., Biotechnol. Bioeng. 100:1132-1143 (2008)). For example,polypeptides (e.g., antibodies) can be analyzed by chromatographicmethods, including but not limited to, liquid chromatography (LC), highperformance liquid chromatography (HPLC), ultra performance liquidchromatography (UPLC), thin layer chromatography (TLC), amide columnchromatography, and combinations thereof.

In other methods, polypeptides (e.g., antibodies) are analyzed by massspectrometry (MS) and related methods, including but not limited to,tandem MS, LC-MS, LC-MS/MS, matrix assisted laser desorption ionisationmass spectrometry (MALDI-MS), Fourier transform mass spectrometry(FTMS), ion mobility separation with mass spectrometry (IMS-MS),electron transfer dissociation (ETD-MS), and combinations thereof.

Other methods of analyzing polypeptides (e.g., antibodies) includeelectrophoretic methods, including but not limited to, capillaryelectrophoresis (CE), CE-MS, gel electrophoresis, agarose gelelectrophoresis, acrylamide gel electrophoresis, SDS-polyacrylamide gelelectrophoresis (SDS-PAGE) followed by Western blotting using antibodiesthat recognize specific amino acids, and combinations thereof.

Yet other analysis methods include nuclear magnetic resonance (NMR) andrelated methods, including but not limited to, one-dimensional NMR(1D-NMR), two-dimensional NMR (2D-NMR), correlation spectroscopymagnetic-angle spinning NMR (COSY-NMR), total correlated spectroscopyNMR (TOCSY-NMR), heteronuclear single-quantum coherence NMR (HSQC-NMR),heteronuclear multiple quantum coherence (HMQC-NMR), rotational nuclearoverhauser effect spectroscopy NMR (ROESY-NMR), nuclear overhausereffect spectroscopy (NOESY-NMR), and combinations thereof.

In some instances, the level of C-terminal variants in a preparation ofpolypeptides (e.g., level of g K0, K1, and/or K2 lysine variants in apreparation of antibodies or Fc-containing polypeptides), produced usinga method described herein can be compared to a target value (e.g.,reference standard), e.g., to make a decision regarding the compositionof the polypeptide preparation, e.g., a decision to classify, select,accept or discard, release or withhold, process into a drug product,ship, move to a different location, formulate, label, package, releaseinto commerce, or sell or offer for sale the polypeptide, e.g., arecombinant antibody. In other instances, the decision can be to accept,modify or reject a production parameter or parameters used to make thepolypeptide, e.g., an antibody. Particular, nonlimiting examples ofreference standards include a control level (e.g., a polypeptideproduced by a different method) or a range or value in a productspecification (e.g., an FDA label or Physician's Insert) or qualitycriterion for a pharmaceutical preparation containing the polypeptidepreparation.

In some instances, methods (i.e., evaluation, identification, andproduction methods) include taking action (e.g., physical action) inresponse to the methods disclosed herein. For example, a polypeptidepreparation is classified, selected, accepted or discarded, released orwithheld, processed into a drug product, shipped, moved to a differentlocation, formulated, labeled, packaged, released into commerce, or soldor offered for sale, depending on whether the preselected or targetvalue is met. In some instances, processing may include formulating(e.g., combining with pharmaceutical excipients), packaging (e.g., in asyringe or vial), labeling, or shipping at least a portion of thepolypeptide preparation. In some instances, processing includesformulating (e.g., combining with pharmaceutical excipients), packaging(e.g., in a syringe or vial), and labeling at least a portion of thepreparation as a drug product described herein. Processing can includedirecting and/or contracting another party to process as describedherein.

In some instances, a biological activity of a polypeptide preparation(e.g., an antibody preparation) is assessed. Biological activity of thepreparation can be analyzed by any known method. In some embodiments, abinding activity of a polypeptide is assessed (e.g., binding to areceptor). In some embodiments, a therapeutic activity of a polypeptideis assessed (e.g., an activity of a polypeptide in decreasing severityor symptom of a disease or condition, or in delaying appearance of asymptom of a disease or condition). In some embodiments, a pharmacologicactivity of a polypeptide is assessed (e.g., bioavailability,pharmacokinetics, pharmacodynamics). For methods of analyzingbioavailability, pharmacokinetics, and pharmacodynamics of glycoproteintherapeutics, see, e.g., Weiner et al., J. Pharm. Biomed. Anal.15(5):571-9, 1997; Srinivas et al., J. Pharm. Sci. 85(1):1-4, 1996; andSrinivas et al., Pharm. Res. 14(7):911-6, 1997.

The particular biological activity or therapeutic activity that can betested will vary depending on the particular polypeptide (e.g.,antibody). The potential adverse activity or toxicity (e.g., propensityto cause hypertension, allergic reactions, thrombotic events, seizures,or other adverse events) of polypeptide preparations can be analyzed byany available method. In some embodiments, immunogenicity of apolypeptide preparation is assessed, e.g., by determining whether thepreparation elicits an antibody response in a subject.

All publications, patent applications, patents, and other referencesmentioned herein are incorporated by reference in their entirety. Inaddition, the materials, methods, and examples are illustrative only andnot intended to be limiting. Unless otherwise defined, all technical andscientific terms used herein have the same meaning as commonlyunderstood by one of ordinary skill in the art to which this inventionbelongs. Although methods and materials similar or equivalent to thosedescribed herein can be used in the practice or testing of the presentinvention, suitable methods and materials are described herein.

The disclosure is further illustrated by the following example. Theexample is provided for illustrative purposes only. It is not to beconstrued as limiting the scope or content of the disclosure in any way.

EXAMPLE Preparation of Antibody with Increased K1 and K2 Lysine ResiduesMethod

The carboxyl-terminal lysine residues of a model antibody produced byCHO cells were analyzed. CL320 CHO cells were grown in a shake flaskinitially in base media (Power CHO2, Catalog #BE15-771, Lonza Inc.,Allendale, N.J.) with 4 mM L-Gln and no other supplements. Cells weregrown for 4 days, and the number of cells increased from 0.54E6/mL to4E6/mL. On Day 4, the cells were fed with 20% Lonza Power Feed A mediumor with 20% Power Feed A medium supplemented with 10 g/L L-Lys or L-Arg.On Day 5, 10 g/L cottonseed hydrolysate was added. VCD and viabilitywere assessed, and cells were harvested on Day 10. The antibodiesproduced under the various conditions were evaluated for titer andC-terminal lysine by ion exchange chromatography.

Results

As shown in FIG. 1, antibodies from cells fed with L-Lys Feed or withL-Arg Feed both had levels of K1 and K2 lysine similar to that of asample of Humira®. Surprisingly, addition of 10 mg/L L-Lys or 10 mg/LL-Arg did not affect growth, viability, or titers. Addition of acombination of L-Lys (10 mg/L) and L-Arg (10 mg/L) resulted in celldeath, which may have been the result of not adjusting the pH toappropriate cell culture levels.

Further, when the antibodies produced were subsequently digested withcarboxypeptidase, the levels of K1 and K2 lysine residues returned tobaseline, indicating that the levels of K1 and K2 were not due tononspecific charge differences (e.g., due to amidation of the antibody).

Additional data showed that a controlled glucose feed resulted inincreased levels of K1 lysines compared to bolus glucose feeds. Withoutwishing to be bound by theory, it is believed that by controllingglucose levels during culture, lactate levels can be reduced, resultingin increased intracellular pH.

Further data showed that the inclusion of NH₄Cl in culture mediaresulted in increased levels of K1 and K2 lysine residues compared tocontrols.

EQUIVALENTS

It is to be understood that while the disclosure has been described inconjunction with the detailed description thereof, the foregoingdescription is intended to illustrate and not limit the scope of theinvention, which is defined by the scope of the appended claims. Otheraspects, advantages, and modifications are within the scope of thefollowing claims.

1-42. (canceled)
 43. A method of producing a preparation of arecombinant antibody, comprising: culturing a cell in a medium underconditions in which the cell expresses a recombinant antibody, whereinthe medium comprises at least about 2 g/L lysine, at least about 2 g/Larginine, at least about 2 g/L histidine, or at least about 2 g/L of acombination of two or more of lysine, arginine, and histidine; andisolating the recombinant antibody, thereby producing a preparation ofthe recombinant antibody.
 44. The method of claim 43, wherein the mediumcomprises: about 2 g/L lysine to about 20 g/L lysine, about 2 g/Larginine to about 20 g/L arginine, about 2 g/L histidine to about 20 g/Lhistidine, or about 2 g/L to about 20 g/L of a combination of two ormore of lysine, arginine, and histidine.
 45. The method of claim 43,wherein the medium comprises about 10 g/L lysine.
 46. The method ofclaim 43, wherein the medium comprises about 10 g/L arginine.
 47. Themethod of claim 43, wherein the medium comprises about 10 g/L histidine.48. The method of claim 43, wherein the medium comprises about 10 g/L ofa combination of two or more of lysine, arginine, and histidine.
 49. Themethod of claim 43, further comprising measuring a level of one or moreC-terminal variants of the recombinant antibody in the preparation. 50.The method of claim 49, wherein the C-terminal variants of therecombinant antibody comprise one or more of a K1 lysine variant of therecombinant antibody and a K2 lysine variant of the recombinantantibody.
 51. The method of claim 50, wherein the level of one or moreof K1 lysine variant and K2 lysine variant in the preparation isincreased relative to a preparation of the recombinant antibody notproduced using a medium comprising at least about 2 g/L lysine, at leastabout 2 g/L arginine, at least about 2 g/L histidine, or at least about2 g/L of a combination of two or more of lysine, arginine, andhistidine.
 52. The method of claim 43, wherein the preparation comprisesa target value of one or more of K1 lysine variants of the recombinantantibody and K2 lysine variants of the recombinant antibody.
 53. Themethod of claim 52, wherein the target value of K1 lysine variants ofthe recombinant antibody is at least 10% of the recombinant antibody inthe preparation.
 54. The method of claim 52, wherein the target value ofK2 lysine variants of the recombinant antibody is at least 4% of therecombinant antibody in the preparation.
 55. The method of claim 43,wherein the host cell is a CHO cell.
 56. The method of claim 43, whereinthe preparation comprises adalimumab.
 57. The method of claim 43,wherein the medium has a pH of about 6.7 to about 7.1.
 58. The method ofclaim 43, wherein the host cell is cultured at a temperature of about31° C. to about 37° C.
 59. The method of claim 43, further comprisingproviding a target value of one or more of K1 lysine variants of therecombinant antibody and K2 lysine variants of the recombinant antibody.60. The method of claim 59, wherein the target value of K1 lysinevariants of the recombinant antibody is at least 10% of the recombinantantibody in the preparation.
 61. The method of claim 59, wherein thetarget value of K2 lysine variants of the recombinant antibody is atleast 4% of the recombinant antibody in the preparation.
 62. The methodof claim 59, wherein the host cell is a CHO cell.
 63. The method ofclaim 62, wherein the preparation comprises adalimumab.
 64. The methodof claim 59, wherein the medium has a pH of about 6.7 to about 7.1. 65.The method of claim 62, wherein the medium has a pH of about 6.7 toabout 7.1.
 66. The method of claim 63, wherein the medium has a pH ofabout 6.7 to about 7.1.
 67. The method of claim 59, wherein the hostcell is cultured at a temperature of about 31° C. to about 37° C. 68.The method of claim 62, wherein the host cell is cultured at atemperature of about 31° C. to about 37° C.
 69. The method of claim 63,wherein the host cell is cultured at a temperature of about 31° C. toabout 37° C.